The vulnerability in the `window.open` method of Mozilla Firefox, Focus for Android, Mozilla Firefox ESR, and the email client Thunderbird allows a hacker to conceal full-screen notifications and perform spoofing attacks.

The vulnerability of the window.open method in Mozilla Firefox, Focus for Android, Mozilla Firefox ESR, and the email client Thunderbird is related to information representation errors in the user interface. Exploiting this vulnerability can allow an attacker to conceal full-screen notifications...