9.1

CVE-2026-33807

Exploit

@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, causing it to never match incoming requests. This results in complete bypass of Express middleware security controls, including authentication, authorization, and rate limiting, for all routes defined within affected child plugin scopes. No special configuration or request crafting is required.

Upgrade to @fastify/express v4.0.5 or later.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Fastify ≫ Fastify/express SwPlatformnode.js Version < 4.0.5
Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.43% 0.342
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
ce714d77-add3-4f53-aff5-83d477b104bb 9.1 3.9 5.2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE-436 Interpretation Conflict

Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state.

https://cna.openjsf.org/security-advisories.html
Vendor Advisory
https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c
Vendor Advisory
Exploit
Mitigation