CVE-2026-100818

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 Widget: Gtk component, which can lead to a sandbox escape. A use-after-free is a memory corruption flaw that occurs when an application continues to use a pointer after it has been freed.

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.