CVE-2026-34457
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.47%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 0.47% probability · 40th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-290
- Affected
- oauth2 proxy project/oauth2 proxy
- Source
- security-advisories@github.com
References
- https://github.com/oauth2-proxy/oauth2-proxy/releases/tag/v7.15.2Release Notes
- https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-5hvv-m4w4-gf6vMitigation, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.