Today the SQL Server Release Services team has published Cumulative Update #8 for SQL Server 2008 R2.
The build number is 10.50.1797, there are 14 fixes showing on the KB article, and this update includes the security update from last week's Patch Tuesday.
No, this patch is not for SQL Server 2008, and no, it is not applicable if you've already installed the CTP of Service Pack 1 for SQL Server 2008 R2 (10.50.2418 or 10.50.2425). Please check @@VERSION before wasting time downloading and trying to install this patch. If @@VERSION returns anything like 10.50.2xxx, 10.00.xxxx or 9.00.xxxx, you should not be installing this cumulative update.