CVE-2026-114642 traefik CVE debrief

Who should care

Defenders and administrators responsible for Traefik deployments should assess their configurations and update to the fixed versions to prevent exploitation. This includes operators managing affected services, platform administrators overseeing Traefik infrastructure, vulnerability management teams tracking exposures, and security teams prioritizing patching and mitigation efforts.

Why it matters

CVE-2026-114642 is a high-severity vulnerability in Traefik that allows unauthenticated clients to bypass TLS verification for services, potentially leading to security risks. Defenders and administrators responsible for Traefik deployments should assess their configurations and update to the fixed versions to prevent exploitation.

• Potential bypass of TLS verification for services
• Unauthenticated clients may access services without proper verification
• Configurations of affected services may need to be reviewed and adjusted

Technical summary

The vulnerability exists because Traefik stores its NTLM/Kerberos backend round tripper in a client-connection slot not keyed by ServersTransport, allowing one service's TLS client configuration to be reused for another service's backend. An unauthenticated client can arm the slot via a backend issuing an NTLM or Negotiate challenge, then reach another service on the same keep-alive connection, bypassing its root CAs, server name, and certificate verification.

Defensive priority

Defenders should prioritize verifying and updating Traefik configurations to prevent exploitation.

Recommended defensive actions

• Verify Traefik versions and configurations to identify potential exposure
• Update Traefik to version 2.11.58 or 3.7.14 to fix the vulnerability
• Review and adjust TLS client configurations for affected services
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and NVD vulnerability detail provide information on the vulnerability, its impact, and affected versions. The vulnerability exists because Traefik stores its NTLM/Kerberos backend round tripper in a client-connection slot not keyed by ServersTransport, allowing one service's TLS client configuration to be reused for another service's backend. Evidence is limited to public CVE and NVD sources. Defenders should verify Traefik configurations and review compensating controls.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.