The FTP service in Cisco AsyncOS on Email Security Appliance (ESA) devices 9.6.0-000 through 9.9.6-026, Web Security Appliance (WSA) devices 9.0.0-162 through 9.5.0-444, and Content Security Management Appliance (SMA) devices allows remote attackers to cause a denial of service via a flood of FTP traffic, aka Bug IDs CSCuz82907, CSCuz84330, and CSCuz86065.