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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2024-11698
• https://bugzilla.mozilla.org/show_bug.cgi?id=1916152
• https://www.mozilla.org/security/advisories/mfsa2024-63
• https://www.mozilla.org/security/advisories/mfsa2024-64
• https://www.mozilla.org/security/advisories/mfsa2024-67
• https://www.mozilla.org/security/advisories/mfsa2024-68