How to close a persistent 'iPhone has been hacked' pop-up in Firefox app on iPhone 14 Pro Max?

First try a forced restart, if that doesn't work reinstall the app. If that doesn't work contact the app developer for help with their software.

Try a forced restart.

• Press and quickly release the volume up button

• Press and quickly release the volume down button

• Press and hold the side button.

• When the Apple logo appears, release the button.

Force restart iPhone - Apple Support (IN) Force restart iPhone - Apple Support (IN)

The issue might be that mobile Firefox is trying to be helpful by re-opening sites that were open the last time that you closed it. If so, you could potentially encounter the same issue with mobile Safari.

You might want to try using Safari to create a shortcut that goes to the URL about:blank . The StackExchange thread suggests that launching the shortcut, instead of tapping on Safari itself, would bypass reopening sites from the previous session. If so, perhaps if you saved such a shortcut and Firefox was your default browser, launching the shortcut would get you into mobile Firefox without reopening the Web site that is presenting the scam popup.

https://apple.stackexchange.com/questions/26909/prevent-mobile-safari-from-loading-the-last-page-when-started

1. Stop visiting the site where you're seeing the pop-up. That's where it's coming from.
2. Install an ad blocker. That alone will kill 99% of the trash ads and pop-ups you'll come across on the web. We use the free Ka-Block! on all of our Apple devices. It's free and available on the App Store.

Edit: To add, all web browsers on iOS must utilize Apple's WebKit rendering engine. In other words, no matter which browser you've installed in iOS, it's still Safari underneath. So there's no point to installing Firefox, Chrome, Opera or anything else.

Personally, I'd dump Firefox and just use Safari.

That, too.