OpenVPN version 2.1.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows attackers via an off-by-one buffer write in the NTLM proxy authentication to potentially cause a crash via a crafted NTLM response from a malicious proxy server
A memory leak in the tls-crypt-v2 client key extraction in OpenVPN 2.5.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote attackers to cause a denial of service (memory exhaustion) via a flood of crafted packets
A memory leak in OpenVPN version 2.5.0 through 2.5.11, 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote attackers with a valid tls-crypt-v2 client key to potentially cause a denial of service
An incorrect buffer size calculation in the epoch key generator in OpenVPN ovpn-dco-win version 2.0.0 through 2.8.3 allows a remote authenticated peer to trigger a heap-based buffer overflow and kernel memory corruption via a crafted data packet, resulting in a system crash (denial of service).
Interactive service agent in OpenVPN version 2.5.0 through 2.6.16 and 2.7_alpha1 through 2.7_rc2 on Windows allows a local authenticated user to connect to the service and trigger an error causing a local denial of service.
OpenVPN version 2.4.0 through 2.6.10 on Windows allows an external, lesser privileged process to create a named pipe which the OpenVPN GUI component would connect to allowing it to escalate its privileges
The interactive service in OpenVPN 2.6.9 and earlier allows the OpenVPN service pipe to be accessed remotely, which allows a remote attacker to interact with the privileged OpenVPN interactive service.
The interactive service in OpenVPN 2.6.9 and earlier allows an attacker to send data causing a stack overflow which can be used to execute arbitrary code with more privileges.
OpenVPN plug-ins on Windows with OpenVPN 2.6.9 and earlier could be loaded from any directory, which allows an attacker to load an arbitrary plug-in which can be used to interact with the privileged OpenVPN interactive service.
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.