CVE-2026-41070: Jkroepke Openvpn-Auth-OAUTH2

Critical severity, CVSS 10.0. EPSS: 0.6% chance of exploitation in the next 30 days.

openvpn-auth-oauth2 is a plugin/management interface client for OpenVPN server to handle an OIDC based single sign-on (SSO) auth flows. From version 1.26.3 to before version 1.27.3, when openvpn-auth-oauth2 is deployed in the experimental plugin mode (shared library loaded by OpenVPN via the plugin directive), clients that do not support WebAuth/SSO (e.g., the openvpn CLI on Linux) are incorrectly admitted to the VPN despite being denied by the authentication logic. The default management-interface mode is not affected because it does not use the OpenVPN plugin return-code mechanism. This issue has been patched in version 1.27.3.

Affected products

• Jkroepke Openvpn-Auth-OAUTH2: from 1.26.3, before 1.27.3 (fixed in 1.27.3)

Published 2026-05-08. Last modified 2026-06-17.