Vulnerability in Traefik
CVE-2026-29777
Traefik is an HTTP reverse proxy and load balancer. Prior to 3.6.10, A tenant with write access to an HTTPRoute resource can inject backtick-delimited rule tokens into Traefik's router rule language via unsanitized header or query parameter match values. In shared gateway deployments, this can bypass listener hostname constraints and redirect traffic for victim hostnames to attacker-controlled backends. This vulnerability is fixed in 3.6.10.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.004 (29.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 29.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Traefik — versions < 3.6.10
Weakness classification (CWE)
References
- github.com/traefik/traefik/security/advisories/GHSA-8q2w-wr49-whqj (Vendor Advisory)
- github.com/traefik/traefik/releases/tag/v3.6.10 (Release Notes)
Frequently asked questions
- What is CVE-2026-29777?
- CVE-2026-29777 is a medium-severity vulnerability in Traefik, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 6.5/10. Published 2026-03-11.
- How severe is CVE-2026-29777?
- Medium severity. CVSS v3 base score is 6.5 out of 10.