CVE-2026-6270

April 17, 2026, 3:17 p.m.

9.1
Critical

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.

Product(s) Impacted

Vendor Product Versions
Fastify
  • Middie
  • *

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-436
Interpretation Conflict
Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state.

*CPE(s)

Affected systems and software identified for this CVE.

Type Vendor Product Version Update Edition Language Software Edition Target Software Target Hardware Other Information
a fastify middie / / / / / / / /

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

Tags

CWE-436
ce714d77-add3-4f53-aff5-83d477b104bb
2026-04-16
CVE-2026-6270

CVSS Score

9.1 / 10

CVSS Data - 3.1

  • Attack Vector: NETWORK
  • Attack Complexity: LOW
  • Privileges Required: NONE
  • Scope: UNCHANGED
  • Confidentiality Impact: HIGH
  • Integrity Impact: HIGH
  • Availability Impact: NONE

    • CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

    View Vector String

Timeline

Published: April 16, 2026, 2:16 p.m.
Last Modified: April 17, 2026, 3:17 p.m.

Status : Undergoing Analysis

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

ce714d77-add3-4f53-aff5-83d477b104bb

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.