Missing namespace checks in Traefik Kubernetes Ingress annotations
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · None · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-862.
Summary
Traefik before 2.11.46, from 3.0.0 before 3.6.17, and from 3.7.0 before 3.7.1 are affected. The Kubernetes Ingress provider does not validate namespaces for Ingress and Service annotations, which allows references to Middlewares, ServersTransports, and TLSOptions in other namespaces (CWE-862). An attacker who can create or update Ingress or Service resources in one namespace can reuse another tenant's injected credentials or client certificates, bypassing namespace-based tenant isolation.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| traefik | traefik | before 2.11.46 | 2.11.46 | Patch available | CNA |
| traefik | traefik | 3.0.0 to before 3.6.17 | 3.6.17 | Patch available | CNA |
| traefik | traefik | 3.7.0 to before 3.7.1 | 3.7.1 | Patch available | CNA |
Remediation
Upgrade Traefik to 2.11.46, 3.6.17, or 3.7.1, matching the release branch in use.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA traefik (traefik) Fixed in 2.11.46
- Fix · CNA traefik (traefik) Fixed in 3.6.17
- Fix · CNA traefik (traefik) Fixed in 3.7.1
Vendor assessments
Timeline
- 2026-10-20 Threatist record created from CVE-2026-112778
- 2026-10-20 Alias added: GHSA-35mp-944w-x8rj
- 2026-10-23 CVSS score added · NVD
- 2026-11-06 Affected versions changed · Red Hat
- 2026-11-06 CVSS score added · Red Hat
References
More Traefik vulnerabilities
- TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
- TI-2023-25774 Uncontrolled Resource Consumption in Traefik CVSS 3.1HIGH 7.5
- TI-2025-40914 Traefik doesn't Prevent Path Normalization Bypass in Router + Middleware Rules CVSS 4.0MEDIUM 6.9
- TI-2022-07529 Authorization header displayed in the debug logs CVSS 3.1MEDIUM 6.5
- TI-2024-30459 HTTP client can remove the X-Forwarded headers in Traefik CVSS 3.1CRITICAL 9.8
- TI-2026-60261 Traefik v3.7.0 Authentication Bypass via from-to-www-redirect CVSS 4.0CRITICAL 9.3
Sources
- CVE-2026-112778 · CVE Program
- CVE-2026-112778 · NVD
- FIRST EPSS
- GHSA-35mp-944w-x8rj · GitHub Advisory Database · CC BY 4.0
- CVE-2026-112778 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences