Last week, Microsoft alerted the public that they would release a number of security patches for Windows 8 and Windows RT as part of the company's regular "Patch Tuesday" monthly updates. Today, those patches were released right on schedule and should be available for automatic download.
In addition to the security patches, there were a number of other software updates made to Windows 8 and Windows RT that were designed to fix general bugs and improve performance. You can see a full list of all the patches that were released today at Microsoft's support web page.
These updates will be the first for both Windows 8 and Windows RT since both operating systems went into general availability on October 26th. These updates should be especially important for owners of Microsoft's Surface and Asus's VivoTab RT tablets, which are currently the only two products on sale to the public that run on on Windows RT.
Overall, eight separate software updates for Windows RT were released today, four of which were security related, and the other four designed to fix bugs and increase performance. Surface owners should expect software updates around this time every month from now on, unless a major security issue prompts Microsoft to issue a quick hotfix.
Source: Microsoft Support web page