One of these is bulletin 1, which affects Microsoft Server platforms. This is where I would prioritize patching efforts because this is potentially a worm-able bug and since Server Core is affected it could apply to a very common service.
Based on the affected systems, Server 2012 and 2008 SP2 are not affected, but Server 2008 release and SP1 are affected, so this is likely something Microsoft has known about for a while and quietly fixed.
The other critical is bulletin 2, which impacts a dogs breakfast of Microsoft operating systems and applications (including Windows 8, RT, and Server 2012); this is likely another broad reaching library bug (a la GDI).
One thing to watch out for in this type of vulnerability is applying all the patches that apply to a system, e.g. it affects, Groove, Office, SharePoint, the OS, and other components. Administrators will have to patch for each affected component.
The other advisories are three privilege elevations, a security bypass and a DoS affecting Windows and .NET.
Author: Ross Barrett, Senior Manager, Security Engineering, at Rapid7.