Vulnerability in Fastify

CVE-2025-32442

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.007 (51.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 51.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-32442: held from 0.007 to 0.007.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: +0.000

Affected products

  • Fastify — versions 4.29.0, >= 5.0.0, < 5.3.2, = 4.29.0

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-32442?
CVE-2025-32442 is a high-severity vulnerability in Fastify, classified under CWE-1287. CVSS score: 7.5/10. Published 2025-04-18.
How severe is CVE-2025-32442?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2025-32442 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.