CVE-2026-6270

CRITICAL EPSS 38.9%
Published Apr 16, 20262mo ago · Modified Jun 17, 20261w ago
9.1 CVSS 3.1
Critical
Find Similar
Published Apr 16, 2026 2mo ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
9.1
Exploitability
3.9
Impact
5.2
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability None

Threat Intelligence

EPSS Exploit Probability
38.9% percentile
Exploit & Patch Status
Public Exploit Known
No Patch Available

Weaknesses 1

CWE-436

Affected Products 1

VendorProductVersionRange
fastifyfastify\/middie* <9.3.2

References 3

  • cna.openjsf.org https://cna.openjsf.org/security-advisories.html
    Vendor Advisory
  • github.com https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c
    ExploitMitigationVendor Advisory
  • github.com https://github.com/fastify/middie/security/advisories/GHSA-72c6-fx6q-fr5w
    Vendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.