Critical (9.8) in mozilla firefox. EPSS 4.0% chance of exploitation in the next 30 days.
Use-after-free vulnerability in the nsRefreshDriver::Tick function in Mozilla Firefox before 49.0, Firefox ESR 45.x before 45.4, and Thunderbird < 45.4 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) by leveraging improper interaction between timeline destruction and the Web Animations model implementation.
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
4.0% chance of exploitation in the next 30 days; higher than 90% of CVEs (scores of 2026-10-31)