OpenVPN ovpn-dco for Windows version 1.1.1 allows an unprivileged local attacker to send I/O control messages with invalid data to the driver resulting in a NULL pointer dereference leading to a system halt.

tap-windows6 driver version 9.26 and earlier does not properly check the size data of incomming write operations which an attacker can use to overflow memory buffers, resulting in a bug check and potentially arbitrary code execution in kernel space