On May 31, Microsoft finally posted SQL Server 2012 Service Pack 1 Cumulative Update 4, which is Build 11.0.3368. This release was about two weeks later than expected, which is a little unusual for Cumulative Updates. I count 38 fixes in the public fix list.
These are probably the two most interesting fixes for the Database Engine:
Remember, this CU is only for SQL Server 2012 Service Pack 1.