Microsoft will issue two bulletins for Patch Tuesday next week--a "critical" one affecting Windows, and an "important" one for Office, the company said today.

Affected software includes Windows Server 2003, Server 2008, Office XP, Office 2003, Office 2007, Office 2004 for Mac and Office 2008 for Mac, according to the advance notice.

The light Patch Tuesday release follows 17 bulletins that Microsoft issued last month.

Microsoft also said it is changing its Exploitability Index, the guide it uses to provide customers information on how likely a vulnerability is of being exploited.

"Specifically, we will be publishing two Exploitability Index ratings per vulnerability--one for the most recent platform, the other as an aggregate rating for all older versions of the software," the company said in a blog post. "This change makes it easier for customers on recent platforms to determine their risk given the extra security mitigations and features built in to Microsoft's newest products; under the previous system, vulnerabilities were given an aggregate rating across all product versions."

c|net