CVE-2026-74976

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 154 Firefox ESR versions prior to 140.14 Firefox ESR versions prior to 153.1 Thunderbird versions prior to 154 Thunderbird versions prior to 140.14 Thunderbird versions prior to 153.1

Description A JIT miscompilation issue exists within the JIT component of the JavaScript Engine. JIT (Just-In-Time) compilation is a method of improving program execution speed by compiling code during runtime rather than before execution.

Recommendations Update Firefox to version 154 or later. Update Firefox ESR to version 140.14 or later. Update Firefox ESR to version 153.1 or later. Update Thunderbird to version 154 or later. Update Thunderbird to version 140.14 or later. Update Thunderbird to version 153.1 or later.