CVE-2026-22031

@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.
Configurations

Configuration 1 (hide)

cpe:2.3:a:openjsf:\@fastify\/middie:*:*:*:*:*:fastify:*:*

History

13 Mar 2026, 14:40

Type Values Removed Values Added
CPE cpe:2.3:a:openjsf:\@fastify\/middie:*:*:*:*:*:fastify:*:*
First Time Openjsf \@fastify\/middie
Openjsf
References () https://github.com/fastify/middie/commit/d44cd56eb724490babf7b452fdbbdd37ea2effba - () https://github.com/fastify/middie/commit/d44cd56eb724490babf7b452fdbbdd37ea2effba - Patch
References () https://github.com/fastify/middie/pull/245 - () https://github.com/fastify/middie/pull/245 - Issue Tracking, Patch
References () https://github.com/fastify/middie/releases/tag/v9.1.0 - () https://github.com/fastify/middie/releases/tag/v9.1.0 - Product, Release Notes
References () https://github.com/fastify/middie/security/advisories/GHSA-cxrg-g7r8-w69p - () https://github.com/fastify/middie/security/advisories/GHSA-cxrg-g7r8-w69p - Exploit, Vendor Advisory

19 Jan 2026, 16:15

Type Values Removed Values Added
New CVE

Information

Published : 2026-01-19 16:15

Updated : 2026-03-13 14:40


NVD link : CVE-2026-22031

Mitre link : CVE-2026-22031

CVE.ORG link : CVE-2026-22031


JSON object : View

Products Affected

openjsf

  • \@fastify\/middie
CWE
CWE-177

Improper Handling of URL Encoding (Hex Encoding)