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High · 7.5 CVE-2026-25223 EUVD-2026-5157GHSA-jx2c-rxcm-jvmq

Fastify's Content-Type header tab character allows body validation bypass

Published Feb 3, 2026 · Updated Sep 16, 2026 · Assigned by GitHub_M

Description

Fastify is a fast and low overhead web framework, for Node.js. Prior to version 5.7.2, a validation bypass vulnerability exists in Fastify where request body validation schemas specified by Content-Type can be completely circumvented. By appending a tab character (\t) followed by arbitrary content to the Content-Type header, attackers can bypass body validation while the server still processes the body as the original content type. This issue has been patched in version 5.7.2.

Affected products

VendorProductAffectedFixed
fastify fastify < 5.7.2 —

Affected packages

EcosystemPackageAffectedFixedRecord
npm fastify < 5.7.2 5.7.2 GHSA-jx2c-rxcm-jvmq

References