.NET Framework 1.0 Service Pack 3 SYSTEM.WEB.DLL and MSCOREE.DLL Security Update for Windows XP Media Center and Windows XP Tablet PC Edition
Publisher's Description
From Microsoft:
A security issue has been identified that could allow an attacker to compromise your Windows-based system running the Microsoft .NET Framework 1.0 and gain complete control over it. You can help protect your computer by installing this update from Microsoft. This version is the first release on CNET Download.com.