Review reviewCritical

CVE-2026-34457

oauth2-proxy oauth2-proxy, oauth2 proxy

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 acces...

CVSS: 9.1
EPSS: 0.47%
CISA KEV: Not listed
Published: 2026.04.15

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.47%

Technical severityCVSS 9.1

Vulnerability overview

Affected product and versions

Product: oauth2-proxy oauth2-proxy, oauth2 proxy
Affected versions: >= < 7.15.2, < 7.15.2
Fixed versions: 7.15.2

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that oauth2-proxy oauth2-proxy, oauth2 proxy and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE: CWE-290