CVE-2026-2880

CRITICAL

9.1

Description

A vulnerability in @fastify/middie versions < 9.2.0 can result in authentication/authorization bypass when using path-scoped middleware (for example, app.use('/secret', auth)). When Fastify router normalization options are enabled (such as ignoreDuplicateSlashes, useSemicolonDelimiter, and related trailing-slash behavior), crafted request paths may bypass middleware checks while still being routed to protected handlers.

CVE Details

CVSS v3.1 Score9.1

SeverityCRITICAL

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published2/27/2026

Last Modified3/19/2026

Sourcenvd

Honeypot Sightings0

Affected Products

openjsf:\@fastify\/middie

Weaknesses (CWE)

CWE-20

References

https://github.com/fastify/middie/security/advisories/GHSA-8p85-9qpw-fwgw(ce714d77-add3-4f53-aff5-83d477b104bb)

IOC Correlations

No correlations recorded

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