CVE-2026-119574 Traefik 3.2.0 before 3.7.15 FastProxy Data Race Denial of Service

What is CVE-2026-119574?

CVE-2026-119574 is a high-severity vulnerability in Traefik, published on 30 Oct 2026.

Official description

Traefik from 3.2.0 before 3.7.15 contains a data race in the experimental FastProxy that allows unauthenticated attackers to crash the process by abusing HTTP/1 protocol upgrades. Attackers can repeatedly open and abort upgraded connections such as WebSocket, corrupting the unsynchronized shared bufio.Reader and triggering an unrecovered panic that terminates Traefik.

Weakness: CWE-567

Which versions are affected by CVE-2026-119574?

It affects 1 product.

Products include Traefik.

How do I fix CVE-2026-119574?

No fix has been published for CVE-2026-119574 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-119574 being exploited?

There is no known exploitation of CVE-2026-119574 in the wild and no public exploit code.

Other vulnerabilities in Traefik

• CVE-2024-45410 HTTP client can remove the X-Forwarded headers in Traefik Critical 9.8
• CVE-2026-88877 Traefik v3.7.0 Authentication Bypass via from-to-www-redirect Critical 9.3
• CVE-2026-85595 Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth Critical 9.3
• CVE-2026-88007 Traefik HTTP/3 Backend NTLM Connection Reuse Critical 9.1
• CVE-2026-88009 Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging High 8.8

All Traefik vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• GitHub advisory
• How this page is made

Also known as GHSA-r4c9-879g-3g2v, GHSA-ww7c-q3mv-xx22.