A vulnerability in the Security Intelligence feed feature of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass the Security Intelligence DNS feed. This vulnerability is due to incorrect feed update processing. An attacker could exploit this vulnerability by sending traffic through an affected device that should be blocked by the affected device. A successful exploit could allow the attacker to bypass device controls and successfully send traffic to devices that are expected to be protected by the affected device.