I believe you're talking about the one listed at the top of the hot news
section at http://www.cdolive.com/
Exchange 5.5 CDO update
This patch resolves problems that were found in the Exchange Server 5.5 CDO
since SP4 was released. This patch includes the fix for KB 818709, Outlook
Web Access Stops Responding When You Try to Access a Mailbox on an Exchange
5.5 Computer.