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
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| traefik | traefik | < 2.11.35, >=3.0.0-beta1, < 3.6.7 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | traefik | 3.6.7-1.1 | openSUSE-SU-2026:10142-1 |
| openSUSE Tumbleweed | traefik2 | 2.11.35-1.1 | openSUSE-SU-2026:10143-1 |
| openSUSE Leap 16.0 | govulncheck-vulndb | 0.0.20260723T184607-160000.1.1 | openSUSE-SU-2026:21483-1 |
| openSUSE Leap 15.6 | govulncheck-vulndb | 0.0.20260123T022811-150000.1.140.1 | SUSE-SU-2026:0292-1 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | traefik-3.4 | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | github.com/traefik/traefik | all versions | — | GO-2026-4322 |
| Go | github.com/traefik/traefik/v2 | < 2.11.35 | 2.11.35 | GHSA-cwjm-3f7h-9hwq |
| Go | github.com/traefik/traefik/v3 | < 3.6.7 | 3.6.7 | GHSA-cwjm-3f7h-9hwq |
Advisories 4
- openSUSE-SU-2026:21483-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Jul 31, 2026
- openSUSE-SU-2026:10142-1 traefik-3.6.7-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- openSUSE-SU-2026:10143-1 traefik2-2.11.35-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:0292-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Mar 23, 2026