CVE-2026-34457

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.

How to fix CVE-2026-34457

To remediate CVE-2026-34457, upgrade the affected package to a fixed version below.

—upgrade to 7.15.2 or later
—no fix listed
—upgrade to 7.15.2 or later

Is CVE-2026-34457 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (3)

from 0, < 7.15.2
from 0, <= 3.2.0
from 0, < 7.15.2

CVSS scores

Source	Version	Severity	Vector
osv	CVSS 3.1	CRITICAL9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N