What’s Vulnerable › Vulnerabilities

CVE-2026-22045: Traefik's ACME TLS-ALPN fast path lacks timeouts and close on handshake stall

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-01-15 · updated 2026-06-17
• Weakness: CWE-770

Description

Traefik is an HTTP reverse proxy and load balancer. Prior to 2.11.35 and 3.6.7, there is a potential vulnerability in Traefik ACME TLS certificates' automatic generation: the ACME TLS-ALPN fast path can allow unauthenticated clients to tie up go routines and file descriptors indefinitely when the ACME TLS challenge is enabled. A malicious client can open many connections, send a minimal ClientHello with acme-tls/1, then stop responding, leading to denial of service of the entry point. The vulnerability is fixed in 2.11.35 and 3.6.7.

Affected products

• Traefik: before 2.11.35; from 3.0.0 before 3.6.7 — fixed in 2.11.35, 3.6.7

How to fix

Upgrade to a fixed version: Traefik 2.11.35, 3.6.7. Check the vendor advisory for mitigations.

References

• https://github.com/traefik/traefik/commit/e9f3089e9045812bcf1b410a9d40568917b26c3d
• https://github.com/traefik/traefik/releases/tag/v2.11.35
• https://github.com/traefik/traefik/releases/tag/v3.6.7
• https://github.com/traefik/traefik/security/advisories/GHSA-cwjm-3f7h-9hwq

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