CVE-2026-41070: openvpn-auth-oauth2 returns FUNC_SUCCESS on client-deny, allowing unauthenticated VPN access
(updated )
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.
References
- github.com/OpenVPN/openvpn/blob/master/include/openvpn-plugin.h.in
- github.com/OpenVPN/openvpn3/blob/master/doc/webauth.md
- github.com/advisories/GHSA-246w-jgmq-88fg
- github.com/jkroepke/openvpn-auth-oauth2/commit/36f69a6c67c1054da7cbfa04ced3f0555127c8f2
- github.com/jkroepke/openvpn-auth-oauth2/pull/829
- github.com/jkroepke/openvpn-auth-oauth2/releases/tag/v1.27.3
- github.com/jkroepke/openvpn-auth-oauth2/security/advisories/GHSA-246w-jgmq-88fg
- nvd.nist.gov/vuln/detail/CVE-2026-41070
Code Behaviors & Features
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