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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-33804 Detail

Description

@fastify/middie versions 9.3.1 and earlier are vulnerable to middleware bypass when the deprecated Fastify ignoreDuplicateSlashes option is enabled. The middleware path matching logic does not account for duplicate slash normalization performed by Fastify's router, allowing requests with duplicate slashes to bypass middleware authentication and authorization checks. This only affects applications using the deprecated ignoreDuplicateSlashes option. Upgrade to @fastify/middie 9.3.2 to fix this issue. There are no workarounds other than disabling the ignoreDuplicateSlashes option.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://cna.openjsf.org/security-advisories.html openjs
https://github.com/fastify/middie/security/advisories/GHSA-v9ww-2j6r-98q6 openjs

Weakness Enumeration

CWE-ID CWE Name Source
CWE-436 Interpretation Conflict openjs  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-33804
NVD Published Date:
04/16/2026
NVD Last Modified:
04/16/2026
Source:
openjs