According to Microsoft, there will be thirteen updates / fixes in total and 8 of them critical. You may have heard about vulnerabilities in Adobe Reader and Acrobat which puts PDF files at risk.
Patches are scheduled for today for Adobe products so make sure you get them. If you have your PC set for automatic updates, they will be installed by themselves.
If you have not, in many cases you will see a yellow shield in the bottom right task tray. You should click on that shield and install the updates. If you do not see the shield, make sure to go to the windows update site and let Microsoft update your computer.