A denial of service vulnerability exists when Microsoft Hyper-V Network Switch on a host server fails to properly validate input from a privileged user on a guest operating system. To exploit the vulnerability, an attacker who already has a privileged account on a guest operating system, running as a virtual machine, could run a specially crafted application that causes a host machine to crash. To exploit the vulnerability, an attacker who already has a privileged account on a guest operating system, running as a virtual machine, could run a specially crafted application.The security update addresses the vulnerability by preventing out-of-bound memory access.