CVE-2026-22045 Traefik's ACME TLS-ALPN fast path lacks timeouts and close on handshake stall
Malicious clients can cause denial of service in Traefik by stalling ACME TLS-ALPN handshakes, exhausting resources when this feature is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-22045?
CVE-2026-22045 is a medium-severity denial of service vulnerability in Traefik Traefik, published on 15 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-770
Which versions are affected by CVE-2026-22045?
7 open source packages ship an affected version, including github.com/traefik/traefik/v2, github.com/traefik/traefik and github.com/traefik/traefik/v3. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/traefik/traefik/v2 Go | All versions | 2.11.35 |
github.com/traefik/traefik/v2 Go | All versions | 2.11.35 |
github.com/traefik/traefik/v2 Go | All versions | 2.11.35 |
github.com/traefik/traefik Go | All versions | None |
github.com/traefik/traefik/v3 Go | All versions | 3.6.7 |
github.com/traefik/traefik/v3 Go | All versions | 3.6.7 |
1 more packages
github.com/traefik/traefik/v3 Go | All versions | 3.6.7 |
Products include Traefik Traefik.
How do I fix CVE-2026-22045?
Upgrade github.com/traefik/traefik/v2 to 2.11.35 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-22045 being exploited?
There is no known exploitation of CVE-2026-22045 in the wild and no public exploit code.
Other vulnerabilities in Traefik Traefik
- CVE-2024-45410 HTTP client can remove the X-Forwarded headers in Traefik
- CVE-2026-88877 Traefik v3.7.0 Authentication Bypass via from-to-www-redirect
- CVE-2026-85595 Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth
- CVE-2026-88007 Traefik HTTP/3 Backend NTLM Connection Reuse
- CVE-2026-88009 Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging
Sources
Also known as CLEANSTART-2026-DQ38367, GHSA-cwjm-3f7h-9hwq, GO-2026-4322, MINI-5636-qgx9-pp49, MINI-r8hg-qqw7-44pq.