CVE-2026-85594

Traefik versions from v3.7.1 fail to enforce crossProviderNamespaces restrictions on the traefik.ingress.kubernetes.io/service.middlewares Service annotation in the Kubernetes Ingress provider. A namespace-limited tenant excluded from the allowlist can attach an operator-owned middleware to its Service, and if that middleware injects backend credentials, recover them at a controlled backend.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/traefik/traefik/security/advisories/GHSA-m6wx-622r-48r9	Exploit Patch Vendor Advisory
https://www.vulncheck.com/advisories/traefik-3.7.1-crossprovidernamespaces-bypass-via-service-middleware	Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*

History

16 Sep 2026, 20:42

Type	Values Removed	Values Added
References	~~() https://github.com/traefik/traefik/security/advisories/GHSA-m6wx-622r-48r9 -~~	() https://github.com/traefik/traefik/security/advisories/GHSA-m6wx-622r-48r9 - Exploit, Patch, Vendor Advisory
References	~~() https://www.vulncheck.com/advisories/traefik-3.7.1-crossprovidernamespaces-bypass-via-service-middleware -~~	() https://www.vulncheck.com/advisories/traefik-3.7.1-crossprovidernamespaces-bypass-via-service-middleware - Third Party Advisory
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 9.8
CPE		cpe:2.3:a:traefik:traefik::::::::
First Time		Traefik Traefik traefik

Information

Published : 2026-09-04 12:17

Updated : 2026-09-16 20:42

NVD link : CVE-2026-85594

Mitre link : CVE-2026-85594

CVE.ORG link : CVE-2026-85594

JSON object : View

Products Affected

traefik

traefik

CWE

CWE-639

Authorization Bypass Through User-Controlled Key

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