CVE-2022-31738: Mozilla Firefox

Medium severity, CVSS 6.5. 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.

Affected products

• Mozilla Firefox: before 101 (fixed in 101)
• Mozilla Firefox ESR: before 91.10 (fixed in 91.10)
• Mozilla Thunderbird: before 91.10 (fixed in 91.10)

Published 2022-12-22. Last modified 2026-06-17.