The SQL Server team has released SQL Server 2012 SP1 Cumulative Update #11. This cumulative update includes a fix for the online index rebuild corruption issue I discussed recently on SQLPerformance.com.
Relevant for builds 11.0.3000 -> 11.0.3448. Do not attempt to install on SQL Server 2012 RTM (any build < 11.0.3000) or any other major version. If you are on a different branch, see this blog post on blogs.sentryone.com for information on the latest fixes for RTM and Service Pack 2.