Vulnerability Description
@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 Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Fastify | Fastify\/Middie | >= 9.1.0, < 9.3.4 |
Related Weaknesses (CWE)
References
- https://cna.openjsf.org/security-advisories.htmlThird Party Advisory
- https://github.com/fastify/middie/security/advisories/GHSA-hx87-8wv7-pjv8MitigationVendor Advisory
FAQ
What is CVE-2026-85184?
CVE-2026-85184 is a vulnerability with a CVSS score of 9.1 (CRITICAL). @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 t...
How severe is CVE-2026-85184?
CVE-2026-85184 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-85184?
Check the references section above for vendor advisories and patch information. Affected products include: Fastify Fastify\/Middie.