CVEvulnerability

CVE-2026-40912

7.8 HIGH Published 2026-04-30 Modified 2026-07-15 Official page ↗
Status
Modified
Published
2026-04-30
Last modified
2026-07-15
Assigner
[email protected]
CVSS 4.0 ([email protected])
7.8 HIGH — CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
8.2 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
CVSS 3.1 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)
8.6 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Weaknesses
CWE-22, CWE-706

Description

Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is a high severity authentication bypass vulnerability in Traefik's StripPrefixRegex middleware when used in combination with ForwardAuth, BasicAuth, or DigestAuth. The middleware matches the regex against the decoded URL path but uses the resulting byte length to slice the percent-encoded raw path. When a dot (or multiple dots) appears in the prefix portion of the URL, the raw path after stripping becomes a dot-segment (e.g. /./admin/secret). ForwardAuth receives this dot-segment path in X-Forwarded-Uri, which does not match the protected path patterns and therefore allows the request through. The backend then normalizes the dot-segment to the real path per RFC 3986 and serves the protected content An unauthenticated attacker can exploit this against any backend that performs dot-segment normalization. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.

Affected configurations

• traefik traefik (< 2.11.43) • traefik traefik (>= 3.0.0 < 3.6.14) • traefik traefik 3.7.0

Related

Weakness · CWE (2)

  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory weakness
  • CWE-706 Use of Incorrectly-Resolved Name or Reference weakness

References