Critical (9.8) in mozilla firefox. EPSS 0.4% chance of exploitation in the next 30 days.
Privilege escalation in the Netmonitor component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
Severity
CVSS 3.1
9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
0.4% chance of exploitation in the next 30 days; higher than 37% of CVEs (scores of 2026-10-31)