CVE-2026-25949 Traefik: TCP readTimeout bypass via STARTTLS on Postgres
An unauthenticated attacker can cause a denial of service in Traefik by bypassing read timeouts via STARTTLS requests.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-25949?
CVE-2026-25949 is a high-severity denial of service vulnerability in Traefik Traefik, published on 12 Feb 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 3.6.8, there is a potential vulnerability in Traefik managing STARTTLS requests. An unauthenticated client can bypass Traefik entrypoint respondingTimeouts.readTimeout by sending the 8-byte Postgres SSLRequest (STARTTLS) prelude and then stalling, causing connections to remain open indefinitely, leading to a denial of service. This vulnerability is fixed in 3.6.8.
Which versions are affected by CVE-2026-25949?
5 open source packages ship an affected version, including github.com/traefik/traefik/v3, github.com/traefik/traefik and github.com/traefik/traefik/v2. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/traefik/traefik/v3 Go | All versions | 3.6.8 |
github.com/traefik/traefik/v3 Go | All versions | 3.6.8 |
github.com/traefik/traefik/v3 Go | All versions | 3.6.8 |
github.com/traefik/traefik Go | All versions | None |
github.com/traefik/traefik/v2 Go | All versions | None |
Linux distribution packages (1)
traefik openSUSE:Tumbleweed | All versions | 3.6.8-1.1 |
Products include Traefik Traefik.
How do I fix CVE-2026-25949?
Upgrade github.com/traefik/traefik/v3 to 3.6.8 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-2026-25949 being exploited?
There is no known exploitation of CVE-2026-25949 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 GHSA-89p3-4642-cr2w, GO-2026-4484, MINI-q234-mpmr-pmpv, MINI-v892-xc4w-xcq8, openSUSE-SU-2026:10217-1.