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.