Today is Patch Tuesday. May's patches consist of 10 updates that correct 32 unique security issues across Microsoft Windows operating systems and some other Microsoft software.
What Do These Security Updates Do?
These patches from Microsoft update several individual files involved in making Windows and other Microsoft software work.
Do I Need These Security Updates?
You need these updates if you're running any currently supported, 32-bit or 64-bit, Windows operating system: Windows 8, Windows 7, Windows Vista, or Windows XP, plus Windows server versions and Windows RT.
Security updates are also being pushed for Microsoft Publisher, Word, Visio, Communicator, and Lync. The free Microsoft Word Viewer and Windows Essentials applications are also being updated to fix security-related issues.
A few of this month's updates fix problems so serious that if left unpatched, it's possible that someone could gain access to your computer in very specific situations. These issues are given a Critical severity rating.
Most of the fixes this month aren't quite as serious but are security issues that should be corrected nonetheless. Some of these were given a severity rating of Important while others were categorized as Moderate.
Are There Any Non-Security Updates This Month?
Yes, including several non-security fixes for Windows 8, Windows RT, Windows 7, and current Windows Server versions. A Root Certificates update is also being pushed out, as well as several .NET Framework 4.5 updates.
Also, as usual, Microsoft is pushing this month's update to the Windows Malicious Software Removal Tool.
There may also be non-security updates included this month for Microsoft software other than Windows. See the Non-Security Updates link below for details.
Patch Tuesday Problems
This blog post has become Grand Central Station for Patch Tuesday problems each month. While updates from Microsoft rarely result in widespread problems with Windows itself, they do frequently cause specific issues with software or drivers provided by other companies.
Please see How To Prevent Windows Updates From Crashing Your PC for a number of preventative measures you should take before applying these updates, including disabling fully automatic updates.
If your computer freezes during the installation of an update, see How To Recover From a Frozen Windows Update Installation for help.
If the updates installed but you're now experiencing a problem, see How To Fix Problems Caused by Windows Updates for advice on how to undo the damage.
See Windows Updates & Patch Tuesday FAQ for answers to other common questions, including "Does Microsoft test these updates before they push them out?" and "Why hasn't Microsoft fixed the problem that their update caused on my computer?!"
Automatically install: via Windows Update.
Details from Microsoft: Microsoft Security Bulletin Summary for May 2013.
Non-Security Updates: New Non-Security Content for 2013.
Next Patch Tuesday: will be June 11, 2013.
A Note on the Comments Below:
I update this blog post for each Patch Tuesday by Microsoft so some of the comments left may be for previous Patch Tuesdays. You can tell which Patch Tuesday a comment is referring to by looking at the notation at the end of the comment. For example, comments addressing Patch Tuesday May 2013 will end with [PT: May 2013].