CVE-2026-6270

9.1 CRITICAL
Published: April 16, 2026 Modified: April 22, 2026
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://cna.openjsf.org/security-advisories.html
Source: ce714d77-add3-4f53-aff5-83d477b104bb
Vendor Advisory
https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c
Source: ce714d77-add3-4f53-aff5-83d477b104bb
Exploit Mitigation Vendor Advisory
https://github.com/fastify/middie/security/advisories/GHSA-72c6-fx6q-fr5w
Source: ce714d77-add3-4f53-aff5-83d477b104bb
Vendor Advisory

3 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.1 / 10.0
EPSS (Exploit Probability)
0.1%
18th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

openjsf