CVE-2026-85594

Critical

Description

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.

SeverityCritical

CVSS9.8

Exploit probability—

Product

Traefik

PublishedSep 4, 2026

First seenSep 4, 2026

Weakness typeCWE-639Authorization bypass through user-controlled key

How to fix

Update

traefik traefik3.7.11 or later

Vendor advisories

github.com/traefik/traefik/security/advisories/GHSA-m6wx-622r-48r9

Affected products

Product	Affected versions	Fixed in
traefik traefik	v < 3.7.11	3.7.11

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