WinXP/2000

An identified security issue in Microsoft® Windows® 2000 and Windows XP could enable an attacker to modify a network's security policies. Network administrators can help protect their networks by installing this update from Microsoft. This update only affects networks running Windows 2000 or Windows XP. Home users and those using workstations on corporate networks do not need this update. Products Affected by This Update
The following products require updating:

Windows XP (Service Pack 1 is not affected; SP1 users need take no action.)
Windows 2000
Important Service Pack 2 (SP2) or Service Pack 3 (SP3) is required to install this update. Users without SP2 or SP3 installed must upgrade their operating systems before trying to install this update. Windows Update scans your computer and recommends only those updates that can be installed on your system. SP2 or SP3 must be present for you to be offered this update.

For more information and patch availablity: 309376