CVE-2026-54763: Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's BasicAuth, DigestAuth, and ForwardAuth middlewares strip canonical-cased spoof

criticalCVSS 10CVE-2026-54763

Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's BasicAuth, DigestAuth, and ForwardAuth middlewares strip canonical-cased spoofed identity headers before writing Traefik's own value, but do not account for underscore-variant header names, which many backends normalize identically to dashed forms. An attacker able to reach a protected route can inject an underscore-variant header that survives Traefik's stripping and reaches the backend alongside, or on the unauthenticated ForwardAuth authResponseHeaders path instead of, the value Traefik intended to set, spoofing identity or authorization context. This issue is fixed in versions v2.11.51, v3.6.22, and v3.7.6.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: critical — CVSS 10
Published: 2026-07-06
Last updated: 2026-07-08
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-54763

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-547630.26% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 17% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-54763	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

unknownMultiple vulnerabilities in Traefik (July 2, 2026)cert-fr-avis

Recent advisories for Traefik is an

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

unknownMultiple vulnerabilities in Traefik (July 09, 2026)cert-fr-avis · 2026-07-09
highCVE-2026-54765: Traefik is an open source HTTP reverse proxy and load balancer. From v3.7.0 prior to v3.7.6, T…nvd · 2026-07-06
mediumCVE-2026-54764: Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Tr…nvd · 2026-07-06
unknownMultiple vulnerabilities in Traefik (July 2, 2026)cert-fr-avis · 2026-07-02
highGHSA-89p3-4642-cr2w: Traefik: TCP readTimeout bypass via STARTTLS on Postgresghsa · 2026-02-12