CVE-2026-54765 traefik vulnerability
Traefik is an open source HTTP reverse proxy and load balancer. From v3.7.0 prior to v3.7.6, Traefik's Kubernetes Gateway API provider may resolve two accepted HTTPRoutes that target the same backend Service:port but configure different backendRef filters to the same child service and apply only one route's filter set to all requests reaching that backend. In Gateway deployments where backendRef filters set security-sensitive headers, such as tenant identity, authorization context, or values the backend trusts, an attacker who can create an accepted HTTPRoute sharing the same backend Service:port may cause their route's filter context to be applied to another route's requests, potentially crossing namespace boundaries when a ReferenceGrant permits cross-namespace targeting. This issue is fixed in version v3.7.6.
Quick answer
traefik should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- Review vendor advisory for affected versions.
Fixed versions
- Apply the latest vendor-supported patched version.
How to fix it
Traefik is affected by CVE-2026-54765, a header trust and authorization bypass risk. Traefik is an open source HTTP reverse proxy and load balancer. The recommended remediation is to update to Traefik 3.7.6 or later for Gateway API deployments. Until the update is complete, review Kubernetes Gateway HTTPRoutes that share backend Service ports with different backendRef filters, review logs, and reduce exposure of the affected service or workflow.
- Inventory every deployment, package, appliance, container, service, and managed environment that uses Traefik.
- Confirm the installed version and compare it with versions prior to v3 and the source advisory for CVE-2026-54765.
- Apply the vendor-supported fix: update to Traefik 3.7.6 or later for Gateway API deployments.
- If the update cannot be applied immediately, review Kubernetes Gateway HTTPRoutes that share backend Service ports with different backendRef filters; disable unnecessary public access, endpoints, integrations, uploads, management interfaces, or high-risk features until patched.
- Review application, device, reverse-proxy, WAF, package manager, container, authentication, and audit logs for activity related to CVE-2026-54765.
- Rotate sessions, API tokens, service credentials, integration keys, and administrator passwords if logs or affected data indicate compromise, code execution, credential exposure, or unauthorized access.
- Clear caches, restart affected services, rebuild affected containers or appliances when appropriate, and remove temporary files, stored payloads, generated artifacts, or unsafe configuration created during exploitation attempts.
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Verify the fix
- Confirm Traefik now reports Traefik 3.7.6 or later for Gateway API deployments or a later vendor-supported fixed release for the deployed branch.
- Verify the affected workflow no longer allows the behavior described in CVE-2026-54765, using a safe regression test or vendor-provided validation method.
- Review logs after remediation for continued exploit attempts, denial-of-service symptoms, suspicious redirects, unauthorized requests, file access, credential exposure, or configuration changes.
- Rerun a Fixnx scan and any product-specific scanner, package audit, device health check, or manual regression test relevant to the affected service.
- Document affected assets, fixed versions, mitigation decisions, validation evidence, and any cleanup or credential rotation performed.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-54765?
traefik should be checked against the vendor advisory and trusted references linked on this page.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.