CVE-2025-6424: firefox: thunderbird: Use-after-free in FontFaceSet

Severity: Critical

CVSS Score: 9.8

A use-after-free in FontFaceSet resulted in a potentially exploitable crash. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.