Fastify up to 5.3.0 on Node.js improper validation of specified type of input

Summaryinfo

A vulnerability described as problematic has been identified in Fastify up to 5.3.0 on Node.js. The affected element is an unknown function. Executing a manipulation can lead to improper validation of specified type of input. The identification of this vulnerability is CVE-2025-32442. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Fastify up to 5.3.0 on Node.js. It has been declared as problematic. This vulnerability affects an unknown code block. The manipulation with an unknown input leads to a improper validation of specified type of input vulnerability. The CWE definition for the vulnerability is CWE-1287. The product receives input that is expected to be of a certain type, but it does not validate or incorrectly validates that the input is actually of the expected type. As an impact it is known to affect integrity. CVE summarizes:

Fastify is a fast and low overhead web framework, for Node.js. In versions 5.0.0 to 5.3.0, applications that specify different validation strategies for different content types have a possibility to bypass validation by providing a _slightly altered_ content type such as with different casing or altered whitespacing before `;`. This issue has been patched in version 5.3.1. A workaround involves not specifying individual content types in the schema.

The advisory is available at github.com. This vulnerability was named CVE-2025-32442 since 04/08/2025. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available.

Upgrading to version 5.3.1 eliminates this vulnerability. Applying the patch 436da4c06dfbbb8c24adee3a64de0c51e4f47418 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-11842). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• JavaScript Library

Name

• Fastify

Version

• 5.0
• 5.1
• 5.2
• 5.3.0

License

• open-source

Website

• Product: https://github.com/fastify/fastify/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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