hi jon, unfortunately this is a scam tactic that is trying to trick you into installing malware, so don't download or execute this kind of stuff just because of a popup or redirect on a website! updates are handled automatically by firefox so you don't have to download anything for that (and you can always initiate a manual check for updates in the firefox menu ≡ > help ? > about firefox).

we suspect this is coming form "malvertising" (=ads placed on legitimate websites that redirect you to this fraudulent message), so using an adblocking addon like https://addons.mozilla.org/firefox/addon/ublock-origin/ would also help with that.

I found a fake Firefox update

jmillsUT28 said

did I looked at the URL and it showed euchupurelols. Is this from Firefox or... The site looked just like your download page.

The orange background and Firefox icon was made by these scammers to make it more believable to those who do not pay attention to the url the site is using in that it is not from a mozilla.org url.

As long as you did not try to run this fake firefox-patch.js file then you should be fine.