This vulnerability allows remote attackers to bypass authentication on affected installations of Ivanti Avalanche 184.108.40.20690. Although authentication is required to exploit this vulnerability, the existing authentication mechanism can be bypassed. The specific flaw exists within the EnterpriseServer service. The issue results from the lack of proper locking when performing operations during authentication. An attacker can leverage this vulnerability to bypass authentication on the system. Was ZDI-CAN-15528.