Memory corruption resulting in a potentially exploitable crash during garbage collection of JavaScript due errors in how incremental sweeping is managed for memory cleanup. This vulnerability affects Firefox < 52, Firefox ESR < 45.8, Thunderbird < 52, and Thunderbird < 45.8.
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
3.4% chance of exploitation in the next 30 days; higher than 88% of CVEs (scores of 2026-10-31)