CVE-2026-84121

A critical use-after-free vulnerability in the DOM security component of Firefox allows for a potential sandbox escape, which could enable attackers to execute arbitrary code within the browser. Users of affected Firefox versions, particularly those running older releases, should prioritize updating to Firefox 155 or the specified ESR versions to mitigate the risk of exploitation. This issue is especially pertinent for organizations relying on Firefox for secure browsing, as it poses a significant threat to user data and system integrity.