CVE-2026-22031 - Fastify Middie Middleware Path Bypass

CVE ID : CVE-2026-22031 Published : Jan. 19, 2026, 3:24 p.m. | 41 minutes ago Description : @fastify/middie is the plugin that adds middleware support on steroids to Fastify. A security vulnerability exists in @fastify/middie prior to version 9.1.0 where middleware registered with a specific path prefix can be bypassed using URL-encoded characters (e.g., `/%61dmin` instead of `/admin`). While the middleware engine fails to match the encoded path and skips execution, the underlying Fastify router correctly decodes the path and matches the route handler, allowing attackers to access protected endpoints without the middleware constraints. Version 9.1.0 fixes the issue. Severity: 0.0 | NA Visit the link for more details, such as CVSS details, affected products, timeline, and more...