On March 17, 2014, Microsoft released SQL Server 2012 Service Pack 1 Cumulative Update 9. This is Build 11.0.3412, and it has 30 hotfixes in the public fix list. This CU is only for SQL Server 2012 Service Pack 1. If you are still on the SQL Server 2012 RTM branch, you do not want this update (and it will not let you install it if you try).
These are two of the more interesting hotfixes:
If you have been paying attention, you may have noticed that Microsoft did not release a SQL Server 2012 RTM CU12 back in mid-February. This means that the RTM branch is close to being retired (although I have not seen an official announcement from Microsoft yet). It also likely means that we are getting closer to seeing SQL Server 2012 SP2 being released (although there is no public date for that yet either). As soon as SP2 is released, Microsoft will probably officially retire the RTM branch.