CVE-2026-71325: Traefik namespace isolation bypass in Kubernetes CRD TraefikService

CVE-2026-71325 · Severity: medium · CVSS 4 · Published 2026-08-06

Traefik is a popular open-source edge router and load balancer. A vulnerability in its Kubernetes integration allows a user who is restricted to one part of a cluster (a namespace) to bypass security boundaries and connect their own traffic rules to services belonging to other users. This could allow an attacker to expose internal services to the public internet or intercept traffic intended for another department or customer.

Technologies: github.com/traefik/traefik (Go), github.com/traefik/traefik/v2 (Go), github.com/traefik/traefik/v3 (Go), Traefik Labs Traefik Proxy. Vendors: Go, Traefik Labs.

Quick answers

Is CVE-2026-71325 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-71325 being exploited in the wild.
How severe is CVE-2026-71325?
Medium severity, with a CVSS score of 4, published 6 August 2026.
Which products and versions are affected?
github.com/traefik/traefik (Go) SEMVER:introduced=0, SEMVER:introduced=0,last_affected=1.7.34; github.com/traefik/traefik/v2 (Go) SEMVER:introduced=0,fixed=2.11.54; github.com/traefik/traefik/v3 (Go) SEMVER:introduced=3.0.0,fixed=3.6.25, SEMVER:introduced=3.0.0,fixed=3.6.25,introduced=3.7.0,fixed=3.7.10.
Is there a fix for CVE-2026-71325?
Yes. github.com/traefik/traefik/v2 (Go): upgrade to 2.11.54 or later; github.com/traefik/traefik/v3 (Go): upgrade to 3.6.25, 3.7.10 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-71325 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-71325?
Check whether you run github.com/traefik/traefik (Go), github.com/traefik/traefik/v2 (Go), github.com/traefik/traefik/v3 (Go) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/traefik/traefik/v2 (Go): upgrade to 2.11.54 or later
    go get github.com/traefik/traefik/v2@v2.11.54
  • github.com/traefik/traefik/v3 (Go): upgrade to 3.6.25, 3.7.10 or later
    go get github.com/traefik/traefik/v3@v3.7.10

Technical details

A vulnerability exists in Traefik's Kubernetes CRD provider where the `allowCrossNamespace=false` setting (the default) is not honored for `TraefikService` backend references. While Traefik correctly enforces this boundary for middlewares and TLS options, the `nameAndService` resolver in `pkg/provider/kubernetes/crd/kubernetes_http.go` lacks the necessary validation logic for names containing the `@kubernetescrd` separator. An attacker with RBAC permissions to create an `IngressRoute` in their own namespace can reference a `TraefikService` in a different namespace, effectively binding their router to a victim's backend. This bypasses the intended multi-tenant isolation. Patches are available in versions 2.11.54, 3.6.25, and 3.7.10.

Affected products

  • Traefik traefik/v2 <= 2.11.53
  • Traefik traefik/v3 >= 3.0.0, <= 3.6.24; >= 3.7.0, <= 3.7.9
  • Traefik traefik <= 1.7.34

Identifiers

  • CVE-2026-71325
  • GHSA-62fc-8686-hfmq
  • GO-2026-6203

Timeline

  • 2026-08-03: advisory: GitHub Advisory published
  • 2026-08-06: disclosed: Public disclosure of CVE-2026-71325

References

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