Medium (4.3) in mozilla. EPSS 0.3% chance of exploitation in the next 30 days.
Form validation popups could capture escape key presses. Therefore, spamming form validation messages could be used to prevent users from exiting full-screen mode. This vulnerability affects Firefox < 128 and Thunderbird < 128.
Severity
CVSS 3.1
4.3 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
EPSS
0.3% chance of exploitation in the next 30 days; higher than 27% of CVEs (scores of 2026-10-31)