CVE-2026-34457
OAuth2 Proxy: Health Check User-Agent Matching Bypasses Authentication in auth_request Mode
OAuth2 Proxy is a reverse proxy that provides authentication using OAuth2 providers. Versions prior to 7.15.2 contain a configuration-dependent authentication bypass in deployments where OAuth2 Proxy is used with an auth_request-style integration (such as nginx auth_request) and either --ping-user-agent is set or --gcp-healthchecks is enabled. In affected configurations, OAuth2 Proxy treats any request with the configured health check User-Agent value as a successful health check regardless of the requested path, allowing an unauthenticated remote attacker to bypass authentication and access protected upstream resources. Deployments that do not use auth_request-style subrequests or that do not enable --ping-user-agent/--gcp-healthchecks are not affected. This issue is fixed in 7.15.2.
| CWE | CWE-290 |
| Vendor | oauth2-proxy |
| Product | oauth2-proxy |
| Published | Apr 14, 2026 |
| Last Updated | Apr 15, 2026 |
Get instant alerts for oauth2-proxy oauth2-proxy
Be the first to know when new critical vulnerabilities affecting oauth2-proxy oauth2-proxy are published — delivered to Slack, Telegram or Discord.
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N