CVE-2026-41070
openvpn-auth-oauth2 returns FUNC_SUCCESS on client-deny, allowing unauthenticated VPN access in github.com/jkroepke/openvpn-auth-oauth2
Description
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.
How to fix CVE-2026-41070
To remediate CVE-2026-41070, upgrade the affected package to a fixed version below.
- —upgrade to 1.27.3-1 or later
- —upgrade to 1.27.3 or later
- —upgrade to 1.27.3 or later
Is CVE-2026-41070 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0, < 1.27.3-1
- >= 1.26.3, < 1.27.3
- >= 1.26.3, < 1.27.3
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N |