Fastify's Missing End Anchor in "subtypeNameReg" Allows Malformed Content-Types to Pass Validation

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

• CISA KEV Not listed.
• EPSS 0.0039, the 33rd percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the GitHub Advisory Database, published 5 Mar 2026. New records show when each source confirmed them.

Sources

• GitHub Advisory Database: GHSA-573f-x89g-hqp9
• OSV: GHSA-573f-x89g-hqp9
• github.com/fastify/fastify/security/advisories/GHSA-573f-x89g-hqp9
• nvd.nist.gov/vuln/detail/CVE-2026-3419
• github.com/fastify/fastify/commit/67f6c9b32cb3623d3c9470cc17ed830dd2f083d7
• cna.openjsf.org/security-advisories.html
• github.com/advisories/GHSA-573f-x89g-hqp9
• github.com/fastify/fastify
• httpwg.org/specs/rfc9110.html#field.content-type
• www.cve.org/CVERecord?id=CVE-2026-3419

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.