OpenVPN 2.1 until v2.4.12 and v2.5.6 may enable authentication bypass in external authentication plug-ins when more than one of them makes use of deferred authentication replies, which allows an external user to be granted access with only partially correct credentials.

furlongm openvpn-monitor through 1.1.3 allows Authorization Bypass to disconnect arbitrary clients.

furlongm openvpn-monitor through 1.1.3 allows %0a command injection via the OpenVPN management interface socket. This can shut down the server via signal%20SIGTERM.

furlongm openvpn-monitor through 1.1.3 allows CSRF to disconnect an arbitrary client.

OpenVPN Access Server 2.9.0 through 2.9.4 allow remote attackers to inject arbitrary web script or HTML via the web login page URL.

OpenVPN 3 Core Library version 3.6 and 3.6.1 allows a man-in-the-middle attacker to bypass the certificate authentication by issuing an unrelated server certificate using the same hostname found in the verify-x509-name option in a client configuration.

OpenVPN before version 2.5.3 on Windows allows local users to load arbitrary dynamic loadable libraries via an OpenSSL configuration file if present, which allows the user to run arbitrary code with the same privilege level as the main OpenVPN process (openvpn.exe).

Securepoint SSL VPN Client v2 before 2.0.32 on Windows has unsafe configuration handling that enables local privilege escalation to NT AUTHORITY\SYSTEM. A non-privileged local user can modify the OpenVPN configuration stored under "%APPDATA%\Securepoint SSL VPN" and add a external script file that is executed as privileged user.

OpenVPN Access Server 2.7.3 to 2.8.7 allows remote attackers to trigger an assert during the user authentication phase via incorrect authentication token data in an early phase of the user authentication resulting in a denial of service.

OpenVPN Access Server 2.8.7 and earlier versions allows a remote attackers to bypass authentication and access control channel data on servers configured with deferred authentication, which can be used to potentially trigger further information leaks.