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

Quick assessment

Affected

traefik traefik

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Traefik 3.2.0 至 3.7.15 版本（不含 3.7.15）的实验性 FastProxy 功能中存在数据竞争漏洞。未认证的攻击者可通过滥用 HTTP/1 协议升级机制（如 WebSocket 连接），反复建立并中断已升级的连接，从而破坏未同步的共享 bufio.Reader 对象，引发无法恢复的 panic，导致 Traefik 进程崩溃。

CVSS 5.9 · Medium Updated Oct 30, 2026

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

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Vulnerability Information

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Vulnerability Title

Traefik 3.2.0 before 3.7.15 FastProxy Data Race Denial of Service

Source: CVE Program / CVE List V5

Vulnerability 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.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Source: CVE Program / CVE List V5

Vulnerability Type

在多现场上下文中未能对共享数据进行同步访问

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
traefik	traefik	3.2.0 ~ 3.7.15	-

II. Public POCs for CVE-2026-119574

#	POC Description	Source Link	Shenlong Link

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No public POC found.

III. Intelligence Information for CVE-2026-119574

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Other References for CVE-2026-119574 (2)

https://github.com/traefik/traefik/security/advisories/GHSA-ww7c-q3mv-xx22 vendor-advisory
https://www.vulncheck.com/advisories/traefik-3.2.0-before-3.7.15-fastproxy-data-race-denial-of-service third-party-advisory

https://www.cve.org/CVERecord?id=CVE-2026-119574

Same Patch Batch · traefik · 2026-10-30 · 3 CVEs total

CVE-2026-119572	8.7 HIGH	Traefik 3.7.0-ea.1 before 3.7.15 mTLS Bypass via Ingress NGINX Provider
CVE-2026-119573	4.4 MEDIUM	Traefik 3.7.11 before 3.7.15 Cross-Namespace Authorization Bypass via auth-tls-secret

IV. Related Vulnerabilities

Same product: traefik

Same vendor: traefik

Same weakness: CWE-567