Vulnerability in Fastify Fastify\/middie
CVE-2026-22031
@fastify/middie is the plugin that adds middleware support on steroids to Fastify. A security vulnerability exists in @fastify/middie prior to version 9.1.0 where middleware registered with a specific path prefix can be bypassed using URL-…
EPSS: 0.001 (34.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L.
Affected products
- Fastify Fastify\/middie
- Fastify Middie — versions < 9.1.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-22031?
- CVE-2026-22031 is a high-severity vulnerability in Fastify Fastify\/middie, classified under CWE-177. CVSS score: 8.4/10. Published 2026-01-19.
- How severe is CVE-2026-22031?
- High severity. CVSS v3 base score is 8.4 out of 10.