Flash Player, Firefox and Linux Mint

You may have noticed the following message when visiting sites in Firefox that use Flash:

"This plugin is vulnerable and should be updated."

While not a show stopper, it is annoying (and possibly concerning... but don't worry, it's not a huge deal).  If you try to update it you'll find that you can't find the current version for Firefox in Linux Mint.  This is an excellent explanation for why:

http://www.howtogeek.com/193876/using-firefox-on-linux-your-flash-player-is-old-and-outdated/?PageSpeed=noscript

The TL;DR: Mozilla doesn't want to support plugin support for Pepper Flash.

Getting around this is relatively easy, though.  Just use FreshPlayerPlugin.  FreshPlayerPlugin simply acts as a wrapper to allow Firefox to work with Pepper Flash.  To use this you'll need to follow these steps:

1. Install Google Chrome.  You don't have to use it, but it's the easiest way to get the libpepflashplayer.so file you need to get this to work.  Do this:

wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | sudo apt-key add -
sudo sh -c 'echo "deb http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google.list'
sudo apt-get update
sudo apt-get install google-chrome-stable

2. Install FreshPlayerPlugin.  Execute these commands:

sudo add-apt-repository ppa:nilarimogard/webupd8
sudo apt-get update
sudo apt-get install freshplayerplugin

Then just exit Firefox and start it up again.  You should be running the latest version of Flash.

Note: As of the day of this posting, hardware acceleration does not work yet, so don't try to mess with the configuration settings to get it to work.  This will be coming eventually.