Microsoft will release four security patches for its Windows, Exchange, and SQL products next Tuesday, all rated "important."

The Exchange and SQL flaws are "Elevation of Privilege" bugs, meaning that an attacker could theoretically exploit them to get administrative access to a PC. One of the Windows flaws is labeled a "spoofing" bug, meaning that it could help hackers trick the user into doing things like visiting malicious Web sites.

The fourth update fixes a Windows flaw that could allow an attacker to run unauthorized code on a victim's PC, Microsoft said. Normally, this type of flaw is rated "critical" by Microsoft, but in this case the bug was probably given a less-severe rating because it doesn't work without the user first taking some extra actions or adding special software or drivers, said Eric Schultze, chief technology officer at Shavlik Technologies.

This remote code execution flaw affects Windows Vista and Windows Server 2008.

The SQL vulnerability affects Microsoft's SQL Server software and the internal SQL software that ships with some versions of Windows. It does not affect Vista or XP users, but it does exist on the Windows 2000, Windows Server 2003 and Windows Server 2008 products.

Microsoft published a note on the upcoming security patches on its Web site on Thursday. Unless it is forced to rush out an emergency fix, the company releases its security patches on the second Tuesday of each month.

Microsoft also said Thursday that it is planning to upgrade the Windows Update software it uses to deliver bug-fixes to PC desktops.

The upgrade will speed up the software download process, said Windows Update Product Manager Michelle Haven in a blog posting. "We’ve invested heavily in reducing the amount of time it takes the Windows Update agent to scan to see if new updates are available," he wrote. "In this case, we’ve seen some instances of the scan times on some machines decreasing almost 20 percent."

Microsoft plans to make further changes to the Windows Update software and back-end infrastructure over the next few months, Haven said.