{"cve":"CVE-2026-22031","nvd":{"published":"2026-01-19T16:15:54.310","modified":"2026-06-17T10:19:23.437","status":"Analyzed","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":8.8},"cwes":["CWE-177"],"references":["https://github.com/fastify/middie/commit/d44cd56eb724490babf7b452fdbbdd37ea2effba","https://github.com/fastify/middie/pull/245","https://github.com/fastify/middie/releases/tag/v9.1.0","https://github.com/fastify/middie/security/advisories/GHSA-cxrg-g7r8-w69p"],"products":["fastify:fastify\\/middie"],"source":"nvd","synced_at":"2026-10-19T22:21:16.563232421+00:00"},"epss":{"cve":"CVE-2026-22031","score":0.00532,"percentile":0.44993,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-cxrg-g7r8-w69p","url":"https://osv.dev/vulnerability/GHSA-cxrg-g7r8-w69p","summary":"Fastify Middie Middleware Path Bypass","modified":"2026-07-08T08:14:42.833760293Z","packages":[{"ecosystem":"npm","name":"@fastify/middie","purl":"pkg:npm/%40fastify/middie","ranges":["<9.1.0"],"fixed":["9.1.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}