User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/113.0

Steps to reproduce:

Browsed an unrelated page (in this case, a the Syncthing admin UI generated from a server running on my own PC)

Actual results:

A pop-up ad for Mozilla VPN appeared on top of the page, and disabled the rest of the Firefox UI until closed. It is shown in the attached screenshot.

Expected results:

The browser should not have displayed an advertisement.

Component: