CVE-2026-119574

Medium

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.

SeverityMedium

CVSS5.9

Exploit probability—

Product

Traefik

PublishedOct 30, 2026

First seenNov 4, 2026

Weakness typeCWE-567CWE-567

How to fix

Update

traefik traefik3.7.15 or later

Vendor advisories

github.com/traefik/traefik/security/advisories/GHSA-ww7c-q3mv-xx22

Affected products

Product	Affected versions	Fixed in
traefik traefik	3.2.0 ≤ v < 3.7.15	3.7.15

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