The Register provides the rundown over here. The critical flaw affects a vulnerability in the Telnet server component of Windows and can lead to remote code execution by sending specifically crafted packets to the Telnet port.
Mind you, most Windows systems aren't running the Telnet server. It comes installed but not enabled by default on Windows Server 2003. It also ships as an option for Windows Vista and later, but it must be explicitly installed via the "Turn Windows features on or off" control panel.Two of the important patches address privilege escalation flaws that were made public by Google earlier this month while other patches update subsystems like Network Location Awareness, Windows Errorr Reporting, the Network Policy Server, and Windows components and drivers.
Additionally, Microsoft is also rolling out a patch that updates the built-in version of Flash for IE10 and IE11 as Adobe just plugged nine holes in its Flash software.