Microsoft has released Service Pack 1 for Office 2013. Please note that "Service Pack 1" or "SP1" does not appear in the version number, unlike previous versions of Office. To confirm that SP1 has been installed, check to see if the version is above 15.0.4569.1506.
Service Pack 1 for 32-Bit versions of Office 2013 is available here:
Service Pack 1 for 64-Bit versions of Office 2013 is available here: