A vulnerability in the TLS processing feature of Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to an issue that occurs when TLS traffic is processed. An attacker could exploit this vulnerability by sending certain TLS traffic over IPv4 through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition and impacting traffic to and through the affected device.
https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75300