CVE-2026-85184 — @fastify/middie vulnerable to path-scoped middleware bypass via absolute-form request target
@fastify/middie versions >= 9.1.0 and before 9.3.4 decide whether to run path-scoped middleware by matching against the raw request target, while the Fastify router resolves an …
Published: 2026-09-04 · CVSS: 9.1 · CVSS 3.1
@fastify/middie versions >= 9.1.0 and before 9.3.4 decide whether to run path-scoped middleware by matching against the raw request target, while the Fastify router resolves an absolute-form request target to its path before dispatching. Because the two layers evaluate different strings, a request using an absolute-form target reaches the route handler while the path-scoped middleware, such as authentication or authorization, is skipped. An unauthenticated network attacker can use this to bypass path-based access controls in a Fastify application that relies on middie for those controls. Users should upgrade to @fastify/middie 9.3.4 or later.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7