A vulnerability in the detection engine of Cisco Firepower System Software could allow an unauthenticated, remote attacker to restart an instance of the Snort detection engine on an affected device, resulting in a brief denial of service (DoS) condition. The vulnerability is due to the incorrect handling of a Transport Layer Security (TLS) extension during TLS connection setup for the affected software. An attacker could exploit this vulnerability by sending a crafted TLS connection setup request to an affected device. A successful exploit could allow the attacker to cause the Snort detection engine on the affected device to restart, resulting in a DoS condition. Cisco Bug IDs: CSCvg97808.