The Redmond, Wash.-based developer will release eight patches for Windows, Office, Exchange, and MSN Messenger, at least half of which will be marked "critical," the company said late Thursday.
The patches will hit on the same day that Microsoft turns off its automatic blocking of Windows XP Service Pack 2 (SP2), which many companies applied last summer when the OS revision released.
According to information posted on Microsoft's Security Bulletin Advance Notification Web site, five of the eight fixes will be for Windows, and one each for Office, Exchange, and MSN Messenger.
Microsoft doesn't hand out details of its upcoming patches when it makes monthly pre-announcements, so the exact nature of the fixes are unknown. The Common Vulnerabilities and Exposures (CVE) database, however, lists a pair of unresolved Office vulnerabilities -- one with InfoPath, the other relating to bypassing policies that limit access to hidden drives by browsing from Office applications -- and one unpatched Exchange issue.
Third-party security firms give other hints of the upcoming patches, although most play it close to the vest. eEye Digital Security, for instance, is a frequent discoverer of Microsoft Windows vulnerabilities, but doesn't disclose details until patches are made public. It does, however, tally the number of vulnerabilities it's found that have not yet been fixed, and marks the number of days since it provided that information to the vendor.
eEye currently lists two vulnerabilities in Windows that it's tagged as "high severity." One was given to Microsoft on March 16, the second on March 29.
Microsoft also said that it would continue the practice of updating its Windows Malicious Software Removal Tool Tuesday by releasing a new version. Two other high-priority updates for Windows will also be posted to the Windows Update site, said Microsoft, although these are not security related.