The vulnerability of Mozilla Firefox, Firefox ESR, and the email client Thunderbird lies in improper restrictions on the displayed layers of the user interface, which allows attackers to perform spoofing attacks.

The vulnerability of Mozilla Firefox, Firefox ESR, and the email client Thunderbird is related to an improper limitation on the visually displayed user interface layers. Exploiting this vulnerability allows a malicious actor to perform spear-phishing attacks using a specially created file with th...