Mozilla · Firefox · CVE-2026-100811
**Name of the Vulnerable Software and Affected Versions**
Firefox versions prior to 157
Firefox ESR versions prior to 153.4
Firefox ESR versions prior to 140.17
Thunderbird versions prior to 157
**Description**
A use-after-free issue exists in the DOM: Core & HTML component, which can lead to a sandbox escape. A use-after-free occurs when a program continues to use a pointer after it has been freed, potentially allowing an attacker to execute arbitrary code outside the restricted sandbox environment.
**Recommendations**
Update Firefox to version 157.
Update Firefox ESR to version 153.4.
Update Firefox ESR to version 140.17.
Update Thunderbird to version 157.