Velocidex WinPmem versions below 4.1 suffer from an Out of Bounds Write vulnerability. By using an IO Control, a user space program can trick the driver into writing a 0 into any chosen memory location. In conjunction with information leakage from the WinPmem driver, attackers can discover the location in memory for the g_CiOptions global symbol. This can be leveraged to disable signed driver enforcement on the target system - allowing attackers to load unsigned drivers.