{"id":"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.","aliases":["BIT-oauth2-proxy-2026-34457","GHSA-5hvv-m4w4-gf6v","GO-2026-5147"],"modified":"2026-07-08T08:13:43.248382795Z","published":"2026-04-14T22:14:38.937Z","database_specific":{"cwe_ids":["CWE-290"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34457.json","cna_assigner":"GitHub_M"},"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"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/oauth2-proxy/oauth2-proxy","events":[{"introduced":"0"},{"fixed":"5961fd99b42c3625b8ef08690d38be5cb37f44b0"}],"database_specific":{"cpe":"cpe:2.3:a:oauth2_proxy_project:oauth2_proxy:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0"},{"fixed":"7.15.2"}],"source":["AFFECTED_FIELD","CPE_RANGE","REFERENCES"]}}],"versions":["v7.15.1","v7.15.0","v7.14.3","v7.14.2","v7.14.1","v7.14.0","v7.13.0","v7.12.0","v7.11.0","v7.10.0","v7.9.0","v7.8.2","v7.8.1","v7.8.0","v7.7.1","v7.7.0","v7.6.0","v7.5.1","v7.5.0","v7.4.0","v7.3.0","v7.2.1","v7.2.0","v7.1.3","v7.1.2","v7.1.1","v7.1.0","v7.0.1","v7.0.0","v6.1.1","v6.1.0","v6.0.0","v5.1.0","v5.0.0","v4.1.0","v4.0.0","v3.2.0","v3.1.0","v3.0.0","v2.2","v2.1","v2.0.1","v2.0","v1.1.1","v1.1","v1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-34457.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"}]}