CVE-2026-71327 in Traefik
Summary
by MITRE • 08/07/2026
Traefik is an open source HTTP reverse proxy and load balancer. From 3.0.0 until 3.6.25 and 3.7.10, Traefik's Kubernetes Gateway API provider in pkg/provider/kubernetes/gateway/httproute.go, grpcroute.go, tcproute.go, and tlsroute.go builds HTTPRoute, GRPCRoute, TCPRoute, and TLSRoute router and service identities by hyphen-concatenating namespace, route name, Gateway identity, entry point, and rule index, allowing colliding Routes to overwrite another namespace's backend. This issue is fixed in 3.6.25 and 3.7.10.
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Analysis
by VulDB Data Team • 08/07/2026
The vulnerability in Traefik's Kubernetes Gateway API provider represents a critical identity collision flaw that undermines the fundamental security boundaries of containerized applications. This issue affects versions from 3.0.0 through 3.6.24 and 3.7.9, where the routing system incorrectly constructs unique identifiers for HTTPRoute, GRPCRoute, TCPRoute, and TLSRoute resources by concatenating namespace, route name, Gateway identity, entry point, and rule index with hyphens. The flawed implementation creates predictable identity patterns that can lead to unauthorized access when multiple namespaces contain routes with identical configurations, enabling malicious actors to exploit the predictable naming scheme to overwrite legitimate routing configurations.
The technical implementation flaw stems from inadequate uniqueness validation within the provider's routing logic, specifically in the pkg/provider/kubernetes/gateway/httproute.go, grpcroute.go, tcproute.go, and tlsroute.go files. When Traefik processes route definitions, it fails to properly namespace or isolate the identifiers generated for different routing resources, creating a scenario where routes from different namespaces can share identical internal identifiers. This design oversight allows an attacker with access to one namespace to potentially manipulate routing decisions for resources in another namespace by crafting route configurations that collide with existing identifiers.
The operational impact of this vulnerability extends beyond simple configuration conflicts, presenting a serious privilege escalation risk within Kubernetes environments. When colliding routes overwrite each other's backend configurations, legitimate applications may be redirected to unintended destinations, potentially exposing sensitive data or creating denial-of-service conditions. This vulnerability particularly affects multi-tenant Kubernetes clusters where multiple teams or applications share the same infrastructure, as it undermines the namespace isolation that Kubernetes provides by default. The attack surface is further expanded when considering that many organizations rely on Traefik for ingress control and external access management, making this a critical concern for production environments.
The flaw aligns with CWE-125 Out-of-Bounds Read and CWE-345 Insufficient Verification of Data Authenticity patterns, as it creates predictable identifiers that can be exploited to manipulate routing decisions without proper authentication or authorization checks. From an ATT&CK framework perspective, this vulnerability maps to T1078 Valid Accounts and T1566 Phishing techniques, as attackers could leverage the predictable routing behavior to redirect traffic to malicious endpoints or establish persistence through manipulated gateway configurations. The vulnerability also relates to T1213 Data from Information Repositories, as it enables unauthorized access to backend services that should remain isolated within their respective namespaces.
Organizations should immediately upgrade to Traefik versions 3.6.25 or 3.7.10 to remediate this vulnerability, as these releases contain proper identity sanitization and namespace isolation mechanisms. Additional mitigations include implementing strict RBAC policies to limit which users can create or modify Gateway API resources, monitoring for unexpected route modifications in the cluster, and validating that all routing configurations properly isolate namespace boundaries. Security teams should also consider implementing network segmentation controls and regular auditing of gateway configurations to detect potential exploitation attempts. The fix addresses the root cause by ensuring that route identifiers incorporate proper namespace scoping and uniqueness validation, preventing the collision scenarios that enabled this class of attacks.