Authentication Bypass Affecting oauth2-proxy package, versions <0:7.15.5-0.1.hum1


Severity

Recommended
high

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.45% (37th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-RHEL10-OAUTH2PROXY-20269916
  • published30 Sept 2026
  • disclosed24 Aug 2026

Introduced: 24 Aug 2026

CVE-2026-76835  (opens in a new tab)
CWE-290  (opens in a new tab)

How to fix?

Upgrade RHEL:10 oauth2-proxy to version 0:7.15.5-0.1.hum1 or higher.
This issue was patched in RHSA-2026:74536.

NVD Description

Note: Versions mentioned in the description apply only to the upstream oauth2-proxy package and not the oauth2-proxy package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

OAuth2 Proxy honours a client-supplied X-Forwarded-Uri header when deciding whether a request may skip authentication, because the guard added for CVE-2026-40575 is inert in the default reverse-proxy configuration. GetRequestURI in pkg/requests/util/util.go prefers that header over the real request URI whenever CanTrustForwardedHeaders returns true, and isAllowedPath in oauthproxy.go matches the skip_auth_routes and skip_auth_regex allow list against the resulting path. CanTrustForwardedHeaders in pkg/apis/middleware/scope.go grants that trust when the caller's address is in the trusted proxy set, and buildTrustedProxyNetSet falls back to defaultTrustedProxyIPs, which is 0.0.0.0/0 and ::/0, whenever reverse proxy mode is enabled without trusted_proxy_ip configured. Every client is therefore treated as a trusted proxy. An unauthenticated attacker can request a protected upstream path while setting X-Forwarded-Uri to a value matching an allow-listed route, so the skip-auth decision is made against the spoofed value while the upstream receives the protected path unchanged.

CVSS Base Scores

version 3.1