A malicious extension could have opened a popup window lacking an address bar. The title of the popup lacking an address bar should not be fully controllable, but in this situation was. This could have been used to spoof a website and attempt to trick the user into providing credentials. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.
This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Firefox | Mozilla | * | 87.0 (excluding) |
| Firefox_esr | Mozilla | * | 78.9 (excluding) |
| Thunderbird | Mozilla | * | 78.9 (excluding) |