CVE-2026-2880

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.

CVSS v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/fastify/middie/security/advisories/GHSA-8p85-9qpw-fwgw	Mitigation Vendor Advisory

Configurations

Configuration 1 (hide)

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

History

No history.

Information

Published : 2026-02-27 19:16

Updated : 2026-03-19 17:30

NVD link : CVE-2026-2880

Mitre link : CVE-2026-2880

CVE.ORG link : CVE-2026-2880

JSON object : View

Products Affected

openjsf

\@fastify\/middie

CWE

CWE-20

Improper Input Validation

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