CVE-2026-33808

Published: Apr 15, 2026 Last Modified: Apr 15, 2026
ExploitDB:
Other exploit source:
Google Dorks:
CRITICAL 9,1
Source: ce714d77-add3-4f53-aff5-83d477b104bb
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Confidentiality: N/A
Integrity: N/A
Availability: N/A

Description

AI Translation Available

Impact@fastify/express v4.0.4 and earlier fails to normalize URLs before passing them to Express middleware when Fastify router normalization options are enabled. This allows complete bypass of path-scoped authentication middleware via duplicate slashes when ignoreDuplicateSlashes is enabled, or via semicolon delimiters when useSemicolonDelimiter is enabled. In both cases, Fastify router normalizes the URL and matches the route, but @fastify/express passes the original un-normalized URL to Express middleware, which fails to match and is skipped. An unauthenticated attacker can access protected routes by manipulating the URL path.

PatchesUpgrade to @fastify/express v4.0.5 or later.

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,0011
Percentile
0,3th
Updated

EPSS Score Trend (Last 2 Days)

436

Interpretation Conflict

Incomplete
Common Consequences
Security Scopes Affected:
Integrity Other
Potential Impacts:
Unexpected State Varies By Context
Applicable Platforms
All platforms may be affected
View CWE Details
https://github.com/fastify/fastify-express/security/advisories/GHSA-6hw5-45gm-f…
https://cna.openjsf.org/security-advisories.html
https://github.com/fastify/fastify-express/security/advisories/GHSA-6hw5-45gm-f…