CVE-2026-84139

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 155 Firefox ESR versions prior to 153.2 Thunderbird versions prior to 155 Thunderbird versions prior to 153.2

Description A clickjacking issue exists within the DOM: Events component. Clickjacking is a technique where an attacker uses multiple transparent or semi-transparent layers to trick a user into clicking on a button or link on another page when they were intending to click on the top-level page.

Recommendations Update Firefox to version 155 or later. Update Firefox ESR to version 153.2 or later. Update Thunderbird to version 155 or later. Update Thunderbird to version 153.2 or later.