CVE-2025-32442 Fastify vulnerable to invalid content-type parsing, which could lead to validation bypass

What is CVE-2025-32442?

CVE-2025-32442 is a high-severity vulnerability in fastify, published on 18 Apr 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Fastify is a fast and low overhead web framework, for Node.js. In versions 5.0.0 to 5.3.0 as well as version 4.29.0, 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 was patched in v5.3.1, but the initial patch did not cover all problems. This has been fully patched in v5.3.2 and v4.29.1. A workaround involves not specifying individual content types in the schema.

Weakness: CWE-1287

Which versions are affected by CVE-2025-32442?

It affects 1 product.

Products include Fastify Fastify.

How do I fix CVE-2025-32442?

Upgrade to a fixed version.

Is CVE-2025-32442 being exploited?

There is no known exploitation of CVE-2025-32442 in the wild and no public exploit code.

Other vulnerabilities in fastify

• CVE-2026-84504 fastify vulnerable to request body replacement via an async validation result collision High 8.1
• CVE-2026-76169 fastify vulnerable to authentication bypass via malformed URLs reaching encapsulated not-found handlers High 7.5
• CVE-2026-84428 fastify vulnerable to header validation bypass via incomplete schema case normalization High 7.5
• CVE-2026-84469 fastify vulnerable to request validation bypass via skipped boolean false schemas High 7.5
• CVE-2026-33806 fastify vulnerable to Body Schema Validation Bypass via Leading Space in Content-Type Header High 7.5

Sources

• CVE record
• NVD
• OSV
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