A total of 12 security bulletins have been released on the November 2015 Patch Day.
Four of the bulletins are rated as critical, the highest available rating, the remaining eight as important, the second highest rating.
Threats range from remote code execution over elevation of privilege to spoofing and information disclosure.
All client versions of Windows are affected by at least one vulnerability in a critical way
For more details : http://www.ghacks.net/2015/11/10/microsoft-security-bulletins-for-november-2015/