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.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Firefox | Mozilla | * | 128.5.0 (excluding) |
| Firefox | Mozilla | * | 133.0 (excluding) |
| Thunderbird | Mozilla | * | 128.5.0 (excluding) |
| Thunderbird | Mozilla | 129.0 (including) | 133.0 (excluding) |