Mozilla · Firefox Esr · CVE-2021-38508
**Name of the Vulnerable Software and Affected Versions**
Firefox versions prior to 94
Thunderbird versions prior to 91.3
Firefox ESR versions prior to 91.3
**Description**
The issue is related to incorrect limitation of visualized user interface layers, potentially allowing a remote attacker to conduct spoofing attacks by hiding requests for access to additional functionality from the user. This can be achieved by displaying a form validity message at the same time as a permission prompt, such as for geolocation, which could obscure the prompt and trick the user into granting the permission.
**Recommendations**
For Firefox versions prior to 94, update to version 94 or later to resolve the issue.
For Thunderbird versions prior to 91.3, update to version 91.3 or later to resolve the issue.
For Firefox ESR versions prior to 91.3, update to version 91.3 or later to resolve the issue.