Microsoft is planning to release three patches tomorrow for this month's Patch Tuesday.
The company said on Friday that the March 10 update will address three issues in Windows 2000, Server 2003, XP, Server 2008 and Windows Vista.
Office and other Microsoft products will not be affected by any fixes this month.
One of the patches was rated by the company as 'critical,' the highest of Microsoft's four alert levels. If exploited, the vulnerabilities addressed by the patch could be exploited by attackers for remote code execution.
The other two patches are being classified as 'important,' the third of four risk levels. Both will address spoofing flaws.
While the company did not disclose the exact details of the vulnerabilities being patched, Microsoft did say that the critical flaw was considered to be a critical risk across all versions of Windows, while one of the 'important' rated patches would not affect systems running Windows XP and Windows Vista.
The update comes just one week after Microsoft issued an 'out of cycle' patch for a flaw in Excel which was being actively exploited in the wild.
That same update also contained a fix to better shore up against attacks making use of the Windows Autorun component.