Node.js up to 20.20.1/22.22.1/24.14.0/25.8.1 req.headersDistinct denial of service

Summaryinfo

A vulnerability classified as problematic has been found in Node.js up to 20.20.1/22.22.1/24.14.0/25.8.1. This impacts an unknown function. The manipulation of the argument req.headersDistinct leads to denial of service. This vulnerability is listed as CVE-2026-21710. The attack may be initiated remotely. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Node.js up to 20.20.1/22.22.1/24.14.0/25.8.1. This issue affects some unknown processing. The manipulation of the argument req.headersDistinct with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. The summary by CVE is:

A flaw in Node.js HTTP request handling causes an uncaught `TypeError` when a request is received with a header named `__proto__` and the application accesses `req.headersDistinct`. When this occurs, `dest["__proto__"]` resolves to `Object.prototype` rather than `undefined`, causing `.push()` to be called on a non-array. This exception is thrown synchronously inside a property getter and cannot be intercepted by `error` event listeners, meaning it cannot be handled without wrapping every `req.headersDistinct` access in a `try/catch`. * This vulnerability affects all Node.js HTTP servers on **20.x, 22.x, 24.x, and v25.x**

It is possible to read the advisory at nodejs.org. The identification of this vulnerability is CVE-2026-21710. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 304242 (Debian dsa-6183 : libnode-dev - security update), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 20.20.2, 22.22.2, 24.14.1 or 25.8.2 eliminates this vulnerability. The upgrade is hosted for download at nodejs.org.

The vulnerability is also documented in the vulnerability database at Tenable (304242). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• JavaScript Library

Name

• Node.js

Version

• 20.20.0
• 20.20.1
• 22.22.0
• 22.22.1
• 24.0
• 24.1
• 24.2
• 24.3
• 24.4
• 24.5
• 24.6
• 24.7
• 24.8
• 24.9
• 24.10
• 24.11
• 24.12
• 24.13
• 24.14.0
• 25.8.0
• 25.8.1

License

• open-source

CPE 2.3info

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CPE 2.2info

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Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

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