CVE-2026-109729

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 158 Firefox ESR versions prior to 115.43 Firefox ESR versions prior to 153.5 Thunderbird versions prior to 158 Thunderbird versions prior to 153.5

Description A use-after-free issue exists within the JIT (Just-In-Time) component of the JavaScript Engine. 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 158 or later. Update Firefox ESR to version 115.43 or later. Update Firefox ESR to version 153.5 or later. Update Thunderbird to version 158 or later. Update Thunderbird to version 153.5 or later.