The Windows kernel-mode drivers in win32k.sys in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, and R2, and Windows 7 do not properly validate an unspecified system-call argument, which allows local users to cause a denial of service (system hang) via a crafted application, aka "Win32k Bounds Checking Vulnerability."