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.
EPSS: 0.003 (19.9th percentile) — read the EPSS interpretation.
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.
Affected products
- Traefik — versions < 3.6.10
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC, 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.