Ubuntu Security Notice 612-10 – USN-612-3 addressed a weakness in OpenSSL certificate and key generation in OpenVPN by adding checks for vulnerable certificates and keys to OpenVPN. A regression was introduced in OpenVPN when using TLS with password protected certificates which caused OpenVPN to not start when used with applications such as NetworkManager.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/67274/USN-612-10.txt
Source: https://packetstormsecurity.com/files/67274/Ubuntu-Security-Notice-612-10.html