Medium (6.5) in mozilla. EPSS 0.6% chance of exploitation in the next 30 days.
When exiting fullscreen mode, an iframe could have confused the browser about the current state of fullscreen, resulting in potential user confusion or spoofing attacks. This vulnerability affects Thunderbird < 91.10, Firefox < 101, and Firefox ESR < 91.10.
Severity
CVSS 3.1
6.5 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
EPSS
0.6% chance of exploitation in the next 30 days; higher than 49% of CVEs (scores of 2026-10-31)