Critical (9.8) in mozilla. EPSS 0.5% chance of exploitation in the next 30 days.
A compromised content process could have allowed for the arbitrary loading of cross-origin pages. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Firefox ESR < 115.16, Thunderbird < 128.3, and Thunderbird < 131.
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
0.5% chance of exploitation in the next 30 days; higher than 45% of CVEs (scores of 2026-10-31)