This vulnerability is marked as “Critical”, and nearly all windows product are affected.
Although it was reported privately to Microsoft and no expolit code leaked now, it is always safer to take action immediately. If you don’t do that, later hackers and worms might be able to attack your machines through RPC service from Internet, and take full control of your machine.
If automatic update is turned on, you will receive the update now. Apply it, make a restart.
For IT Pros, you need to check this for details:
In case you need to download the files manually:
Microsoft Windows 2000 Service Pack 4
Remote Code Execution
Windows XP Service Pack 2
Windows XP Service Pack 3
Windows XP Professional x64 Edition
Windows XP Professional x64 Edition Service Pack 2
Windows Server 2003 Service Pack 1
Windows Server 2003 Service Pack 2
Windows Server 2003 x64 Edition
Windows Server 2003 x64 Edition Service Pack 2
Windows Server 2003 with SP1 for Itanium-based Systems
Windows Server 2003 with SP2 for Itanium-based Systems
Windows Vista and Windows Vista Service Pack 1
Windows Vista x64 Edition and Windows Vista x64 Edition Service Pack 1
Windows Server 2008 for 32-bit Systems*
Windows Server 2008 for x64-based Systems*
Windows Server 2008 for Itanium-based Systems
Although this is only a security fix for the OS, as a SharePoint Developer/Administrator, you will always be responsibile for the security issues. So let’s prevent things from happen at the beginning.