CRITICAL: CVE-2026-6270 (CVSS 9.1) — fastify fastify\/middie
CVE: CVE-2026-6270
CVSS: 9.1 (3.1) — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Severity: CRITICAL
Status: Critical advisory
Affected
- fastify fastify\/middie
Summary
@fastify/middie versions 9.3.1 and earlier do not register inherited middleware directly on child plugin engine instances. When a Fastify application registers authentication middleware in a parent scope and then registers child plugins with @fastify/middie, the child scope does not inherit the parent middleware. This allows unauthenticated requests to reach routes defined in child plugin scopes, bypassing authentication and authorization checks. Upgrade to @fastify/middie 9.3.2 to fix this issue. There are no workarounds.
Verified Sources
References
- https://cna.openjsf.org/security-advisories.html
- https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c
- https://github.com/fastify/middie/security/advisories/GHSA-72c6-fx6q-fr5w
_Validated by the Lyrie Threat Intelligence Pipeline — 3 independent sources confirmed before publication. No speculation._
Lyrie Verdict
A vulnerability of this severity is exactly what Lyrie's anti-rogue-AI defense is built for: continuous, autonomous monitoring that doesn't wait for human reaction time.
Validated sources
- [1]NVD
- [2]GitHub Advisory
- [3]MITRE