Mitigation Strategies

To mitigate this vulnerability, upgrade Traefik to one of the patched versions: 2.11.43, 3.6.14, or 3.7.0-rc.2.

Ensure that the configuration setting providers.kubernetesCRD.allowCrossNamespace is set to false to enforce cross-namespace isolation.

Useful 0 Not Useful 0

Executive Summary

This vulnerability exists in Traefik's Kubernetes CRD provider cross-namespace isolation enforcement. When the setting providers.kubernetesCRD.allowCrossNamespace is set to false, Traefik correctly blocks direct cross-namespace middleware references from IngressRoute objects. However, it fails to enforce this restriction on middleware references that are nested inside a Chain middleware's spec.chain.middlewares[].

As a result, an actor who has permission to create or update Traefik CRDs in their own namespace can exploit this flaw to cause Traefik to resolve and apply middleware objects from another namespace, effectively bypassing the intended isolation boundary.

This issue was fixed in Traefik versions 2.11.43, 3.6.14, and 3.7.0-rc.2.

Useful 0 Not Useful 0

Impact Analysis

This vulnerability can allow an attacker with limited permissions in one namespace to bypass namespace isolation and apply middleware configurations from another namespace. This could lead to unauthorized modification of traffic routing or processing behavior in Traefik, potentially impacting the security and stability of services running in other namespaces.

Useful 0 Not Useful 0

Compliance Impact

This vulnerability allows unauthorized cross-namespace middleware binding in Traefik's Kubernetes CRD provider, potentially enabling an attacker with limited permissions to apply middleware from another namespace. Such unauthorized access and policy bypass could lead to improper enforcement of security controls and data handling policies.

While the CVE description and resources do not explicitly mention compliance with standards like GDPR or HIPAA, the ability to bypass namespace isolation and apply middleware across namespaces could undermine data segregation and access controls required by these regulations.

Therefore, organizations relying on Traefik for Kubernetes ingress and middleware enforcement should consider this vulnerability as a risk to maintaining strict isolation and control over data and processing flows, which are critical for compliance with regulations that mandate data protection and access restrictions.

Useful 0 Not Useful 0

Detection Guidance

This vulnerability involves Traefik's Kubernetes CRD provider incorrectly allowing cross-namespace middleware references inside Chain middlewares when the allowCrossNamespace setting is false.

To detect this vulnerability on your system, you should check your Traefik version to see if it is prior to the patched versions (2.11.43, 3.6.14, or 3.7.0-rc.2).

Additionally, inspect your Kubernetes CRD configurations for Chain middlewares that reference middlewares in other namespaces despite allowCrossNamespace being set to false.

• Use kubectl commands to list Chain middlewares and check their nested middleware references for cross-namespace usage, for example:
• kubectl get middlewares -A -o yaml | grep -B 5 -A 5 'chain:'
• Look specifically for entries under spec.chain.middlewares[].namespace that differ from the namespace of the Chain middleware itself.
• Check Traefik logs for errors related to cross-namespace middleware references if allowCrossNamespace is false, as patched versions log such errors.

Useful 0 Not Useful 0