Microsoft will release six sets of security patches next Tuesday, four of which will fix critical flaws in the Windows operating system.

The software will be released as part of Microsoft's regular monthly security release, known informally as "Patch Tuesday". Microsoft is also planning less-critical updates for Visio and Windows Vista, the company said in a note, yesterday.

The critical Windows updates fix flaws in Internet Explorer, Outlook Express, Windows Mail, and other core components of the operating system, Microsoft said.

Microsoft considers an update critical when the flaw could be used by an attacker to remotely run unauthorised software on the victim's machine, theoretically leading to the propagation of an internet worm.

This month, Microsoft has revealed a few more details on the upcoming patches than it has in the past. That's part of a new plan to help IT administrators better prepare for Patch Tuesday by letting them know exactly what versions of Microsoft's products will be affected by the updates.

Microsoft is slightly ahead of its 2006 patch rate. By June of 2006, the company had released 32 security updates. With these six updates, the June 2006 tally will be 35.

Last month, Microsoft released seven groups of patches on Patch Tuesday.