The information in this article applies to:
Microsoft Windows XP Professional, Home Edition
Microsoft Windows 2000 Professional
Microsoft Windows NT, Workstation 4.0, Server 4.0, Server 4.0 Terminal Server Edition

The Microsoft Locator service is a name service that maps logical names to network-specific names. It is included with Windows NT 4.0, Windows 2000, & Windows XP. A security vulnerability results from an unchecked buffer in the Locator service. By sending a specially malformed request to the Locator service, an attacker might cause the Locator service to stop working, or to run code on your computer.

Patch availability (http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS03-001.asp)