OpenVPN Access Server before 2.11 uses a weak random generator used to create user session token for the web portal

The OpenVPN Access Server installer creates a log file readable for everyone, which from version 2.10.0 and before 2.11.0 may contain a random generated admin password

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 Connect 3.2.0 through 3.3.0 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 (OpenVPNConnect.exe).

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).