CVE-2026-6270
@fastify/middie vulnerable to middleware authentication bypass in child plugin scopes
Severity by source
Trivy's own label is CRITICAL. Rated critical by GHSA.
Description
@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.
Affected packages and fixed versions
| Source | Package | Fixed in |
|---|---|---|
| npm::GitHub Security Advisory npm | @fastify/middie | 9.3.2 |