Unspecified vulnerability in Cisco ASA 5500 Series Adaptive Security Appliance 7.2 before 7.2(4.46), 8.0 before 8.0(4.38), 8.1 before 8.1(2.29), and 8.2 before 8.2(1.5); and Cisco PIX 500 Series Security Appliance; allows remote attackers to cause a denial of service (prevention of new connections) via crafted TCP segments during termination of the TCP connection that cause the connection to remain in CLOSEWAIT status, aka "TCP Connection Exhaustion Denial of Service Vulnerability."