The zip API endpoint in Cerberus FTP Server 8 allows an authenticated attacker without zip permission to use the zip functionality via an unrestricted API endpoint. Improper permission verification occurs when calling the file/ajax_download_zip/zip_name endpoint. The result is that a user without permissions can zip and download files even if they do not have permission to view whether the file exists.
https://www.doyler.net/security-not-included/cerberus-ftp-vulnerabilities
https://support.cerberusftp.com/hc/en-us/community/topics/360000164199-Announcements