CVSS 3.1
9.1 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NCVE-2026-6270
Critical (9.1) in fastify fastify\/middie. EPSS 0.5% chance of exploitation in the next 30 days. Fixed in @fastify/middie 9.3.2.
@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.
Severity
- EPSS
- 0.5% chance of exploitation in the next 30 days; higher than 42% of CVEs (scores of 2026-10-31)
- CWE
- CWE-436
- Published
- Modified
- Record from
- the NVD, synced
Affected
- fastify:fastify\/middie
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-72c6-fx6q-fr5w | npm | @fastify/middie | <9.3.2 | 9.3.2 |