When in an endless loop, a website specifying a custom cursor using CSS could make it look like the user is interacting with the user interface, when they are not. This could lead to a perceived broken state, especially when interactions with existing browser dialogs and warnings do not work. This vulnerability affects Firefox ESR < 78.1, Firefox < 79, and Thunderbird < 78.1.
The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Firefox | Mozilla | * | 79.0 (excluding) |
| Firefox_esr | Mozilla | * | 78.1 (excluding) |
| Thunderbird | Mozilla | * | 78.1 (excluding) |