"The critical update covers flaws in Excel, Windows Active Directory, and .NET Framework. All create a possible means for hackers to inject hostile code onto vulnerable systems (remote code execution). Separate security bugs in Internet Information Server (Microsoft's web server software) and Microsoft Office Publisher also carry the same risk but earn a lower classification of "important" from Redmond. Microsoft's security gnomes have also addressed a "moderate" security bug in Windows firewall that creates an information disclosure risk."

Paper Link: http://www.channelregister.co.uk/2007/07/11/ms_patch_tuesday/