CVE-2024-11698: Mozilla Firefox

Critical severity, CVSS 9.8. EPSS: 0.7% chance of exploitation in the next 30 days.

A flaw in handling fullscreen transitions may have inadvertently caused the application to become stuck in fullscreen mode when a modal dialog was opened during the transition. This issue left users unable to exit fullscreen mode using standard actions like pressing "Esc" or accessing right-click menus, resulting in a disrupted browsing experience until the browser is restarted. *This bug only affects the application when running on macOS. Other operating systems are unaffected.* This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.

Affected products

• Mozilla Firefox: before 128.5.0 (fixed in 128.5.0); before 133.0 (fixed in 133.0)
• Mozilla Thunderbird: before 128.5.0 (fixed in 128.5.0); from 129.0, before 133.0 (fixed in 133.0)

Published 2024-11-26. Last modified 2026-06-17.