Anyone else notice that MS07-051 disappeared today? I was working on this vulnerability, when I noticed the link stopped responding. All that remains is the reference from the September bulletin page:

Bulletin Identifier: Microsoft Security Bulletin MS07-051

Bulletin Title: Vulnerability in Microsoft Agent Could Allow Remote Code Execution (938827)

Executive Summary: This critical security update resolves a privately reported vulnerability. A remote code execution vulnerability exists in Microsoft Agent in the way that it handles certain specially crafted URLs. The vulnerability could allow an attacker to remotely execute code on the affected system. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

Maximum Severity Rating: Critical

Impact of Vulnerability: Remote Code Execution

Detection: Microsoft Baseline Security Analyzer can detect whether your computer system requires this update. The update will require a restart.

Affected Software: Windows. For more information, see the Affected Software and Download Locations section.

Patch if you can.