@fastify/express v4.0.4 and earlier contains a path handling bug in the onRegister function that causes middleware paths to be doubled when inherited by child plugins. When a child plugin is registered with a prefix that matches a middleware path, the middleware path is prefixed a second time, causing it to never match incoming requests. This results in complete bypass of Express middleware security controls, including authentication, authorization, and rate limiting, for all routes defined within affected child plugin scopes. No special configuration or request crafting is required. Upgrade to @fastify/express v4.0.5 or later.
Fix
Patch, vendor advisory and mitigation references on NVD 3
- https://cna.openjsf.org/security-advisories.html Vendor Advisory
- https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c Exploit, Mitigation, Vendor Advisory
- https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c Exploit, Mitigation, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 9.1 · fastifyNVD modified 2026-10-26 21:10
Affected (CPE criteria) 1
cpe:2.3:a:fastify:fastify\/express:*:*:*:*:*:node.js:*:*
References 3
- https://cna.openjsf.org/security-advisories.html Vendor Advisory
- https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c Exploit, Mitigation, Vendor Advisory
- https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c Exploit, Mitigation, Vendor Advisory