hello, this is a scam tactic that is trying to trick you into installing malware, so don't download or execute this kind of stuff! only download firefox from its official location at mozilla.org - in addition updates are handled automatically by firefox so you don't have to download anything (you can initiate a check for updates in the firefox menu ≡ > help ? > about firefox).

in case this is caused by rogue advertisements on legitimate websites, you could install an adblocking extension in firefox: https://addons.mozilla.org/firefox/addon/ublock-origin/

you might also want to run a full scan of your system with the security software already in place and different tools like the free version of malwarebytes, adwcleaner & kaspersky security scan in order to make sure that there isn't already some sort of malware active on your system that triggers these false alerts.

Troubleshoot Firefox issues caused by malware

mdrstardeck said

How do I know when a spamer is using Firefox logo? A full orange screen popped with Firefox logo and said I needed to do an urgent download to solve a problem. I didn't know where to go to check this out.

Well for starters if it is not a *mozilla.org url or redirects to a *mozilla.org url then it is likely not from Mozilla.

https://wiki.mozilla.org/Over_100_domains

Nothing stops people from using a few product words and a product logo on a page and claiming it is official even if website has a weird name url.

I started a thread listing the sites serving fake Firefox update/patch exe at https://support.mozilla.org/en-US/forums/contributors/712056 and as you can see the urls alone should raise a flag to people encountering it.