CVE-2026-41174
Fix: traefik/traefik@df00d82CVE-2026-41174 is a CWE-653 vulnerability in github.com/traefik/traefik/v3. O3 Security confirms whether CVE-2026-41174 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Traefik Kubernetes CRD allows unauthorized cross-namespace middleware binding
Real-World Exposure
github.com/traefik/traefik/v3🐹github.com/traefik/traefik/v3🐹github.com/traefik/traefik/v2🐹github.com/traefik/traefikReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is a potential vulnerability in Traefik's Kubernetes CRD provider cross-namespace isolation enforcement. When providers.kubernetesCRD.allowCrossNamespace=false, Traefik correctly rejects direct cross-namespace middleware references from IngressRoute objects, but fails to apply the same restriction to middleware references nested inside a Chain middleware's spec.chain.middlewares[]. An actor with permission to create or update Traefik CRDs in their own namespace can exploit this to cause Traefik to resolve and apply middleware objects from another namespace, bypassing the documented isolation boundary. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/traefik/traefik/v3 | ≥ 3.7.0-ea.1&&< 3.7.0-rc.2 | 3.7.0-rc.2 |
| 🐹Go | github.com/traefik/traefik/v3 | ≥ 3.0.0-beta1&&< 3.6.14 | 3.6.14 |
| 🐹Go | github.com/traefik/traefik/v2 | all versions | 2.11.43 |
| 🐹Go | github.com/traefik/traefik | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/traefik/traefik/v3. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/traefik/traefik/v3 to 3.7.0-rc.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-41174 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-41174 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-41174. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-41174 in your dependencies?
O3 detects CVE-2026-41174 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.