Flash should auto update (if you use Google Chrome it's built in and updated). You can also go to adobe.com to make sure. Just be sure to UNCHECK whatever add on software they try to include when you grab the latest version. My ITXpert clients will always get the latest version even if auto update is broken.

Bitdefender:

Adobe fixed 18 critical flaws in Flash Player: updates are made automatically for browser plug-ins.
We advise you to make sure the auto update feature from the desktop Flash Player release is turned on. http://bit.ly/Adobe_fix_