CVE-2026-112778: Traefik before 2.11.46, 3.6.17, and 3.7.1 Cross-Namespace Resource Reference via Kubernetes Annotations

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-19 · updated 2026-10-23
Weakness: CWE-862

Description

Traefik before 2.11.46, 3.x before 3.6.17, and 3.7.0 lack namespace validation for Ingress and Service annotations in the Kubernetes Ingress provider, allowing references to Middlewares, ServersTransports, and TLSOptions in other namespaces. Attackers able to create or update Ingress or Service resources in one namespace can set router.middlewares or service.serverstransport annotations to obtain another tenant's injected credentials or reuse its client certificates, bypassing namespace-based tenant isolation.

Affected products

Traefik: before 2.11.46; from 3.0.0 before 3.6.16; 3.7.0 (and their updates) — fixed in 2.11.46, 3.6.16

How to fix

Upgrade to a fixed version: Traefik 2.11.46, 3.6.16. Check the vendor advisory for mitigations.

References

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