Vulnerability Description
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.38 and 3.6.9, there is a potential vulnerability in Traefik managing TLS handshake on TCP routers. When Traefik processes a TLS connection on a TCP router, the read deadline used to bound protocol sniffing is cleared before the TLS handshake is completed. When a TLS handshake read error occurs, the code attempts a second handshake with different connection parameters, silently ignoring the initial error. A remote unauthenticated client can exploit this by sending an incomplete TLS record and stopping further data transmission, causing the TLS handshake to stall indefinitely and holding connections open. By opening many such stalled connections in parallel, an attacker can exhaust file descriptors and goroutines, degrading availability of all services on the affected entrypoint. This issue has been patched in versions 2.11.38 and 3.6.9.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Traefik | Traefik | < 2.11.38 |
Related Weaknesses (CWE)
References
- https://github.com/traefik/traefik/releases/tag/v2.11.38ProductRelease Notes
- https://github.com/traefik/traefik/releases/tag/v3.6.9ProductRelease Notes
- https://github.com/traefik/traefik/security/advisories/GHSA-xw98-5q62-jx94PatchVendor Advisory
FAQ
What is CVE-2026-26999?
CVE-2026-26999 is a vulnerability with a CVSS score of 7.5 (HIGH). Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.38 and 3.6.9, there is a potential vulnerability in Traefik managing TLS handshake on TCP routers. When Traefik processes a T...
How severe is CVE-2026-26999?
CVE-2026-26999 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-26999?
Check the references section above for vendor advisories and patch information. Affected products include: Traefik Traefik.