Find, fix and prevent vulnerabilities in your code.

Overview

Affected versions of this package are vulnerable to Prototype Pollution via mergeObject(), which fails to validate keys before writing them to target objects. An attacker can supply a malicious source object containing a __proto__ key in a merge operation, injecting attacker-controlled properties into the prototype of the returned object and causing applications to inherit unintended values when accessing properties without own-property checks. We score this differently from NVD: prototype pollution that achieves property injection into Object.prototype with no authentication and no user interaction warrants a High integrity impact, consistent with the supplied CVSS vectors.

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:

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 deepmerge.

References

• GitHub Issue
• Vulnerable Code

Overview

ioredis is a Redis client for Node.js.

Affected versions of this package are vulnerable to Uncontrolled Recursion in the RESP protocol parser in lib/parser.js. An attacker can crash the Node.js client process by sending crafted RESP byte streams with repeated nested array headers. The parser recurses while handling nested arrays, exhausting the V8 call stack and triggering an uncaught RangeError. In affected deployments that consume data from a malicious or compromised Redis endpoint, this terminates the process and disrupts Redis client operations.

Remediation

Upgrade ioredis to version 6.0.0-beta.1 or higher.

References

• GitHub Issue
• GitHub PR
• Vulnerable Code
• Vulnerable Code
• Vulnerable Code decoder.ts:646-713

Overview

node-forge is a JavaScript implementations of network transports, cryptography, ciphers, PKI, message digests, and various utilities.

Affected versions of this package are vulnerable to Improper Verification of Cryptographic Signature in rsa.js, whose DigestInfo validation checks the outer element count (obj.value.length !== 2) but never verifies the element count of the inner DigestAlgorithm SEQUENCE, so the ASN.1 parser accepts extra children that are ignored during digest extraction. An attacker can forge a signature that verifies as valid for an arbitrary message, without the private key, by fixing the target digest at the block boundaries and filling roughly 314 garbage bytes inside the DigestAlgorithm structure to absorb the mathematical residue. This only affects verification against RSA keys with a low public exponent such as e=3, and although _parseAllDigestBytes defaults to true and rejects trailing garbage, it does not detect this interior padding.

Note: This is a bypass of the fix for the vulnerability described in CVE-2026-33894 and, as of this publication, has not been acknowledged by project maintainers.

Remediation

A fix was pushed into the master branch but not yet published.

References

• github.com
• github.com
• GitHub Issue

Overview

zod is a TypeScript-first schema declaration and validation library with static type inference

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling via the handleArrayResult parse logic in $ZodArray, which accumulates every validation issue for each failing element in a large array with no cap or early termination. An attacker can submit a large array to an application using an array schema without a length constraint, causing the process to allocate excessive issue objects and crash due to out-of-memory conditions.

Remediation

There is no fixed version for zod.

References

• GitHub Issue
• GitHub PR