{"id":"CVE-2026-34457","aliases":["BIT-oauth2-proxy-2026-34457","GHSA-5hvv-m4w4-gf6v","GO-2026-5147"],"url":"https://o3.security/vulnerability/CVE-2026-34457","summary":"OAuth2 Proxy: Health Check User-Agent Matching Bypasses Authentication in auth_request Mode","details":"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.","published":"2026-04-14T22:14:38.937Z","modified":"2026-08-05T03:32:33.092888206Z","cvss":{"score":9.1,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/oauth2-proxy/oauth2-proxy/v7","fixedVersion":"7.15.2"},{"ecosystem":"Go","name":"github.com/oauth2-proxy/oauth2-proxy","fixedVersion":null}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/oauth2-proxy/oauth2-proxy/releases/tag/v7.15.2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34457.json"},{"type":"ADVISORY","url":"https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-5hvv-m4w4-gf6v"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34457"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-05T03:32:33.092888206Z"}}