Description

OAuth2-Proxy is an open-source tool that can act as either a standalone reverse proxy or a middleware component integrated into existing reverse proxy or load balancer setups. In versions 7.10.0 and below, oauth2-proxy deployments are vulnerable when using the skip_auth_routes configuration option with regex patterns. Attackers can bypass authentication by crafting URLs with query parameters that satisfy configured regex patterns, allowing unauthorized access to protected resources. The issue stems from skip_auth_routes matching against the full request URI. Deployments using skip_auth_routes with regex patterns containing wildcards or broad matching patterns are most at risk. This issue is fixed in version 7.11.0. Workarounds include: auditing all skip_auth_routes configurations for overly permissive patterns, replacing wildcard patterns with exact path matches where possible, ensuring regex patterns are properly anchored (starting with ^ and ending with $), or implementing custom validation that strips query parameters before regex matching.

Weaknesses 1

Affected Products 1

References 6

• github.com https://github.com/oauth2-proxy/oauth2-proxy/blob/f4b33b64bd66ad28e9b0d63bea51837b83c00ca1/oauthproxy.go#L582-L584
  Product
• github.com https://github.com/oauth2-proxy/oauth2-proxy/blob/f4b33b64bd66ad28e9b0d63bea51837b83c00ca1/pkg/requests/util/util.go#L37-L44
  Product
• github.com https://github.com/oauth2-proxy/oauth2-proxy/commit/9ffafad4b2d2f9f7668e5504565f356a7c047b77
  Patch
• github.com https://github.com/oauth2-proxy/oauth2-proxy/releases/tag/v7.11.0
  Release Notes
• github.com https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-7rh7-c77v-6434
  ExploitMitigationVendor Advisory
• oauth2-proxy.github.io https://oauth2-proxy.github.io/oauth2-proxy/configuration/overview/#proxy-options
  Product

Remediation

• github.com https://github.com/oauth2-proxy/oauth2-proxy/commit/9ffafad4b2d2f9f7668e5504565f356a7c047b77
  Patch