CVE-2021-34793

CVE-2021-34793 describes a denial-of-service vulnerability in Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software when operating in transparent mode. An unauthenticated, remote attacker can exploit this by sending crafted TCP segments, leading to MAC address table poisoning in adjacent devices and network disruption. With a CVSS score of 8.6 (HIGH), this vulnerability is easily exploitable over the network with low attack complexity, but there is no evidence of active exploitation, publicly available exploit code, or significant community discussion.