Critical (9.8). EPSS 7.0% chance of exploitation in the next 30 days.
A use-after-free vulnerability can occur during font face manipulation when a font face is freed while still in use, resulting in a potentially exploitable crash. This vulnerability affects Thunderbird < 52.6, Firefox ESR < 52.6, and Firefox < 58.
Severity
CVSS 3.0
9.8 critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
7.0% chance of exploitation in the next 30 days; higher than 94% of CVEs (scores of 2026-10-31)