📌 이 취약점에 대해 확인된 사실
전부 발행처가 발표한 값입니다. 우리가 계산하거나 판단한 숫자는 하나도 없습니다.
악용 여부
심각도 (발행처 발표값)
보통5.3
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/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
악용 확률 (EPSS)
0.2%
📄 원문 그대로
아래 문장은 전부 발행처가 쓴 것입니다. 번역하지 않습니다 — 보안 문서의 오역은 조치를 바꿉니다.
취약점 설명 (NVD)
Traefik is an HTTP reverse proxy and load balancer. In Traefik v1.x, v2.x through v2.11.55, and v3.0.0 through v3.7.11, header names are canonicalized only on dashes, so X-Auth-User, X_Auth_User and X.Auth.User are treated as three distinct headers by Traefik, while backends that derive variable names from header names (CGI, WSGI, PHP, NGINX and others) collapse them into a single variable. A client can therefore smuggle a dot-form alias of a header that Traefik manages past the middleware managing it — for example supplying X.Authenticated.User alongside the canonical X-Authenticated-User written by the ForwardAuth middleware — causing such a backend to read the client-supplied value instead of the identity Traefik asserted. In the tested configuration (PHP 8.2 built-in SAPI over an HTTP/1 backend path), Go's lexical header ordering makes the attacker-supplied value win deterministically, so a client that ForwardAuth admits as a low-privilege identity can be treated by the backend as a different user or role. Any header Traefik sets is affected, not only ForwardAuth's. This is an incomplete fix for GHSA-x677-9fxg-v5c5, which blocked only the underscore form. Fixed in v2.11.56 and v3.7.12, which add the aliasHeadersStrategy entry-point option; because it defaults to 'keep' for backwards compatibility, it must be explicitly set to 'delete' or 'reject' for the fix to take effect. Unmaintained release lines will not receive a patch.
참고
악용 확률 변화
우리가 매일 저장한 EPSS 스냅샷입니다. 원본은 전날 값만 주므로, 이 표는 수집을 시작한 이후만 보여줍니다.
| 기준일 | 확률 | 백분위 |
|---|---|---|
| 2026-09-15 | 0.21% | 10.9% |
| 2026-09-14 | 0.27% | 18.4% |
| 2026-09-13 | 0.27% | 18.4% |
| 2026-09-12 | 0.27% | 18.5% |
| 2026-09-11 | 0.27% | 18.4% |
🧩 같은 약점 유형 — CWE-290
같은 분류의 다른 취약점입니다. 같은 실수가 제품을 가리지 않고 반복됩니다.