CVE-2026-85184

@fastify/middie versions >= 9.1.0 and before 9.3.4 decide whether to run path-scoped middleware by matching against the raw request target, while the Fastify router resolves an absolute-form request target to its path before dispatching. Because the two layers evaluate different strings, a request using an absolute-form target reaches the route handler while the path-scoped middleware, such as authentication or authorization, is skipped. An unauthenticated network attacker can use this to bypass path-based access controls in a Fastify application that relies on middie for those controls. Users should upgrade to @fastify/middie 9.3.4 or later.

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://cna.openjsf.org/security-advisories.html	Third Party Advisory
https://github.com/fastify/middie/security/advisories/GHSA-hx87-8wv7-pjv8	Mitigation Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:fastify:fastify\/middie:*:*:*:*:*:node.js:*:*

History

No history.

Information

Published : 2026-09-04 10:17

Updated : 2026-09-15 20:02

NVD link : CVE-2026-85184

Mitre link : CVE-2026-85184

CVE.ORG link : CVE-2026-85184

JSON object : View

Products Affected

fastify

fastify\/middie

CWE

CWE-436

Interpretation Conflict

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