Raphael Saniyazov

**Name of the Vulnerable Software and Affected Versions** Firefox versions prior to 130 **Description** The issue is related to the notification announcing the transition to fullscreen mode in Firefox on Android. Multiple prompts and panels from both Firefox and the Android OS could be used to obscure this notification, potentially leading to spoofing of the browser UI if the user is distracted by the sudden appearance of a prompt. The notifications now use the Android Toast feature. This issue only affects Firefox on Android, with other operating systems being unaffected. **Recommendations** For versions prior to 130, update to Firefox version 130 or later to resolve the issue. As a temporary workaround, consider being cautious when multiple prompts appear, ensuring to notice any visual transitions to fullscreen mode. Restricting the use of fullscreen mode until the update can also minimize the risk of exploitation.

Name of the Vulnerable Software and Affected Versions: Firefox versions prior to 56 Description: A spoofing issue occurs when a page switches to fullscreen mode without user notification, allowing a fake address bar to be displayed. This enables an attacker to spoof the actual page loaded and in use. The issue is related to insufficient input validation when using fullscreen mode. It may allow a remote attacker to conduct spoofing attacks by replacing the page or URI. This issue specifically affects Firefox for Android, with other operating systems not being affected. Recommendations: For versions prior to 56, update to version 56 or later to resolve the issue. As a temporary workaround, consider disabling fullscreen mode until a patch is available. Restrict access to untrusted websites to minimize the risk of exploitation.