Being redirected from one URL to another does not indicate that Firefox downloaded (much less installed) malware. You should run malware scans as you normally would just in case.

Hi, I already ran Malwarebytes and Win Defender as soon as I closed the fake captcha site. Nothing was detected. I'm not worried about malware being downloaded but only if the Firefox browser data from the main windows user account could be stolen by running an infostealer on the guest account. The guest account had Vanilla Firefox with zero extensions and seemingly no accounts on it as seen by Google defaulting to light mode. I want to believe nothing's wrong but I can't be too sure. I apologize if I seem like I'm overreacting, I just had too many coincidences today that I just had to ask.

I'm only aware of infostealers that execute outside the browser and exfiltrate files. I'm not aware of any infostealers that run from a web page, since content scripts should be restricted to same-site or same-tab data.

If that's the case, then I'll assume I'm fine. However I didn't take any chances and backed up my files and nuked the installation. Thanks for assisting, maybe I'm just overly worried even though I didn't run the script. Nothing else comes up on google too when I search fy3 dot fit. Anyway, I'll mark this as solved, thanks.