Five of the bulletins address "critical" flaws, two address "important" bugs and one addresses a "moderate" flaw, according to an advance notification bulletin. Of the five critical patches, three involve Windows issues, one affects Internet Explorer and the other involves Excel.
In late February, Microsoft announced that a vulnerability in Excel was being exploited in targeted attacks. However, Microsoft will not reveal which hole the Excel fix -- which affects Office 2000, XP, 2003, 2007 and Office for Mac versions -- plugs prior to Tuesday's release.
The patches labeled important fix flaws in Windows and Microsoft Internet Security & Acceleration Server (ISA), while the moderate patch addresses at least one more bug in Windows.
The update is expected to be released around 2 p.m. EST Tuesday and will include, as always, the latest Malicious Software Removal Tool.