I was on Mountain Lion and Firefox whined that current flash player was vulnerable. However, I couldn't seems to get a regular setup file to work properly.

Adobe Flash Player Setup

I've tried to install many times, including doing uninstaller and reinstalling. Nothing worked. It always didn't response to mouse cursor at an auto-update choices dialog.

Solution: Download offline setup file from http://www.adobe.com/products/flashplayer/distribution3.html and everything will be fine once again. I surely hope Adobe addresses this soon.