Vulnerability · Published Oct 30, 2026 · Assigned by VulnCheck

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

Medium 5.9

In plain English

A medium-severity security flaw in traefik from traefik. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities).

Severity (CVSS 3.1)5.9Medium

Exploit odds (30 days)0.3%top 79.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
traefik	traefik	3.2.0 – before 3.7.15

Weakness: CWE-567 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

GitHub Security Advisory (GHSA-ww7c-q3mv-xx22) vendor-advisory
VulnCheck Advisory: Traefik 3.2.0 before 3.7.15 FastProxy Data Race Denial of Service third-party-advisory