Race condition in the Health and Performance Monitoring (HPM) for ASDM feature in Cisco ASA Software 8.3 before 8.3(2.42), 8.4 before 8.4(7.11), 8.5 before 8.5(1.19), 8.6 before 8.6(1.13), 8.7 before 8.7(1.11), 9.0 before 9.0(4.8), and 9.1 before 9.1(4.5) allows remote attackers to cause a denial of service (device reload) via TCP traffic that triggers many half-open connections at the same time, aka Bug ID CSCum00556.