win32k.sys in the kernel-mode drivers in Microsoft Windows Server 2008 R2 and Windows 7 does not properly validate user-mode input, which allows local users to gain privileges via a crafted application, aka "Win32k Memory Corruption Vulnerability."
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.