Summary
Traefik Kubernetes CRD allows unauthorized cross-namespace middleware binding
Impact
This is an authorization / trust-boundary bypass in Traefik's Kubernetes CRD provider.
Clusters that rely on providers.kubernetesCRD.allowCrossNamespace=false for namespace isolation are affected. An actor who is allowed to create or update Traefik CRDs in their own namespace can still cause Traefik to apply middleware from another namespace by referencing it indirectly through a local Chain middleware.
The practical impact depends on which middleware objects exist in the other namespace, but this can allow unauthorized reuse of security-sensitive or policy-bearing middleware across namespace boundaries. Examples include request modification, header manipulation, authentication or forward-auth related behavior, and other traffic-handling policies that were intended to remain namespace-scoped.
Testers have not verified unauthenticated remote compromise, code execution, or universal cross-tenant data exposure. The core issue is that a documented isolation control can be bypassed through the nested Chain middleware reference path.
The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.
CVE-2026-41174 has a CVSS score of 6.4 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.7.0-rc.2, 3.6.14, 2.11.43); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Frequently Asked Questions
- What is CVE-2026-41174? CVE-2026-41174 is a medium-severity incorrect authorization vulnerability in github.com/traefik/traefik/v3 (go), affecting versions >= 3.7.0-ea.1, < 3.7.0-rc.2. It is fixed in 3.7.0-rc.2, 3.6.14, 2.11.43. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
- How severe is CVE-2026-41174? CVE-2026-41174 has a CVSS score of 6.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2026-41174?
github.com/traefik/traefik/v3(go) (versions >= 3.7.0-ea.1, < 3.7.0-rc.2)github.com/traefik/traefik/v2(go) (versions < 2.11.43)github.com/traefik/traefik(go) (versions <= 1.7.34)
- Is there a fix for CVE-2026-41174? Yes. CVE-2026-41174 is fixed in 3.7.0-rc.2, 3.6.14, 2.11.43. Upgrade to this version or later.
- Is CVE-2026-41174 exploitable, and should I be worried? Whether CVE-2026-41174 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-41174 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-41174?
- Upgrade
github.com/traefik/traefik/v3to 3.7.0-rc.2 or later - Upgrade
github.com/traefik/traefik/v3to 3.6.14 or later - Upgrade
github.com/traefik/traefik/v2to 2.11.43 or later
- Upgrade