The kernel in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP2, Vista Gold, SP1, and SP2, and Server 2008 Gold and SP2 does not properly validate a registry-key argument to an unspecified system call, which allows local users to cause a denial of service (reboot) via a crafted application, aka "Windows Kernel Null Pointer Vulnerability."