I have a Debian x86_64 system with Firefox installed from Mozilla's tar.gz.
On the addons page (hit CONTROL+SHIFT+A then go to the Plugins tab) there is a link: "Check to see if your plugins are up to date." When I click on it displays: Shockwave Flash 11.2 r202 vulnerable. When I click on "Update now" the version presented to me to download is:
Adobe Flash Player version 11.2.202.291
Your system: Linux 64-bit, Firefox
Which is the same I already have.
Additional information
The version string in Add-ons Manager's Plugin tab is: Shockwave Flash 11,2,202,291
# /usr/sbin/update-flashplugin-nonfree --status
Flash Player version installed on this system : 11.2.202.291
Flash Player version available on upstream site: 11.2.202.291
flash-mozilla.so - auto mode
link currently points to /usr/lib/flashplugin-nonfree/libflashplayer.so
/usr/lib/flashplugin-nonfree/libflashplayer.so - priority 50
Current 'best' version is '/usr/lib/flashplugin-nonfree/libflashplayer.so'.