Mozilla · Firefox · CVE-2021-43540
**Name of the Vulnerable Software and Affected Versions**
Firefox versions prior to 95
**Description**
The issue allows WebExtensions with the correct permissions to create and install ServiceWorkers for third-party websites. These ServiceWorkers would not be uninstalled when the extension is removed.
**Recommendations**
For versions prior to 95, update to version 95 or later to resolve the issue.