There's a somewhat puzzling thread on Adobe's support forum about MacOS X 10.8.5:

"While we've dropped support for OS X 10.8 we did not block installation on that version. Flash Player will still install." https://forums.adobe.com/thread/2222384

So... I think it makes sense to go to the "other versions" page and say you have a later version of MacOS and try to install that way:

https://get.adobe.com/flashplayer/otherversions/

Does it work?

To jscher2000,

It's working so far - - yaaaaaay - - thank you very much!

I just fixed ONE plugin, but I still cannot fix the Acrobat Plugin which it says is VULNERABLE (NOT MY FAULT OF COURSE) so why then is there no update? We deserve an update from both FF and Adobe.

MILLIONS Of us still use 10.8.5 because it is the last best RECOGNIZABLE Mac system and we won't go further until Apple gets its act together again and makes the Mac look and work like a Mac!

I have pledged to donate $1000 to FF if they would update the browser for thousands of us who need this fix.

Mozilla does not make or maintain any of the Plugins from Adobe.

Past versions of Adobe Acrobat and Reader for Windows and Macintosh are indeed affect by critical vulnerabilities. https://helpx.adobe.com/security/products/acrobat/apsb17-01.html

Full Acrobat Reader can be downloaded from the https://get.adobe.com/reader/otherversions/ including versions for OSX 10.6.4 and later.

James said

Mozilla does not make or maintain any of the Plugins from Adobe. Past versions of Adobe Acrobat and Reader for Windows and Macintosh are indeed affect by critical vulnerabilities.

No kidding. But they say it's because FireFox is not up to date for this OS. So if you updated FF, then I could update the 'vulnerable' Adobe plugin! I have also asked Adobe to reconsider updating, after all the vulnerability affects millions of us!