The 3rd cumulative update release for SQL Server 2012 SP3 is now available for download at the Microsoft Support site.
To learn more about the release or servicing model, please visit:
•CU#13 KB Article: https://support.microsoft.com/en-us/kb/3152635
•Understanding IncrementalServicingModel for SQL Server
•SQL Server Support Information: Microsoft SQL Server
•Update Center for Microsoft SQL Server: Update Center for Microsoft SQL Server
Source: The 3rd cumulative update release for SQL Server 2012 SP3 is now available for download | SQL Server Release Services