GHSA-HRWM-HGMJ-7P9C @fastify/express's middleware path doubling causes authentication bypass in child plugin scopes

Summary @fastify/express v4.0.4 contains a path handling bug in the onRegister function that causes middleware paths to be doubled when inherited by child plugins. This results in complete bypass of Express middleware security controls for all routes defined within child plugin scopes that share ...

CVE-2026-33807 @fastify/express vulnerable to middleware path doubling causing authentication bypass in child plugin scopes

@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,...

CVE-2026-33807

CVE-2026-33807 affects @fastify/express v4.0.4 and earlier. A path handling bug in onRegister doubles middleware paths when inherited by child plugins, causing the middleware to never match requests. This results in complete bypass of Express middleware security controls (authentication, authoriz...