Five of the 11 bulletins will be rated "critical," Microsoft's highest severity rating. The flaws affect all versions of Windows, including the company's newest Windows 7 operating system.
The vulnerabilities will address security holes in Windows, Microsoft Office, and Microsoft Exchange, according to Jerry Bryant, a group manager in Redmond's security response center.
Bryant also confirmed that the April batch of patches will include fixes for two publicly known issues:
Windows users can find all the affected software and severity ratings in the Microsoft's advance notice summary.
If you're on Twitter, you can receive updates from the MSRC at the new @MSFTSecResponse account.