I'm using a ThinkPad t14 notebook with Windows 11 Pro 64bits version 23H2, with Mozilla Firefox version 129.0.2

I'm using a ThinkPad t14 notebook with Windows 11 Pro 64bits version 23H2, with Mozilla Firefox version 129.0.2.
I accessed with Mozilla to an infected site, and the Kaspersky Internet Security application don't detect it. More over: I run a full scan, and it report 1 file uninfected and quarantined, but trying yo identify the file, the Quarantine entry for the Kasperksy menu does not show any file.

Nevertheless, starting Mozilla immediately appears a message from the virus (see the attached file). The virus message content changes every time I access Mozilla, but it has every time the same structure.

I refreshed Mozilla and the virus apparently disappear.

Is it safe continuing using Mozilla? Do I need to make a deep clean of my notebook?

@Carlos Isa Welcome.

Can you please post a screenshot from the Kaspersky report ?

↓ Kaspersky Threat Intelligence Portal ↓

Also, check the FF add-on / extensions installed, check also in FF settings -> Privacy & Security -> Rights, the Web Site Notifications allowed, since I guess that is just a fake notification sent from an allowed site:

 

Here are the Report screenshots. Second screen obtained in the 1 object disinfected link.

 

Hos can I see which file was disinfected?

 

The Kaspersky protection is enabled, and the notifications configuration is standard:

Hum ok, You can try to run this tool: AdwCleaner, once ended the scan, copy/paste the log of result in Your next post.