VMware is "a software virtualization system which allows multiple virtual computers to run on a single system. VMware Tools provides drivers and utilities to enhance and optimize the experience within a guest operating system running under VMware". Local exploitation of a input validation vulnerability within VMware's Hgfs.sys driver could allow an unprivileged attacker to execute arbitrary code within the kernel of a Windows guest operating system.

http://www.securiteam.com/windowsntf...TP011POKG.html