A vulnerability in the detection engine of Cisco Firepower System Software could allow an unauthenticated, remote attacker to bypass file policies that are configured to block files transmitted to an affected device via the BitTorrent protocol. The vulnerability exists because the affected software does not detect BitTorrent handshake messages correctly. An attacker could exploit this vulnerability by sending a crafted BitTorrent connection request to an affected device. A successful exploit could allow the attacker to bypass file policies that are configured to block files transmitted to the affected device via the BitTorrent protocol. Cisco Bug IDs: CSCve26946.