The vulnerability of Thunderbird email client, Firefox and Firefox ESR browsers is related to an incorrect limitation on the number of visible layers or frames in the user interface during the reportValidity operation. This allows a hacker to bypass the full-screen notification and perform a spoofing attack.

The vulnerability of the Thunderbird email client, as well as Firefox and Firefox ESR browsers, is related to an incorrect limitation on the number of visible layers or frames in the user interface during the reportValidity process. Exploiting this vulnerability allows a remote attacker to bypass...