A vulnerability was found in the nsconfigd daemon (TCP port 3008/SSL and 3010). This daemon can be crashed by sending a specially crafted message. No prior authentication is necessary. A watchdog daemon (pitboss) automatically restarts nsconfigd after the first six crashes and then reboots the appliance. By sending just a few packets the appliance can be kept in a constant reboot loop resulting in total loss of availability. The vulnerabilities have been verified to exist in Citrix NetScaler VPX (Build 70.7.nc), which was the most recent version at the time of discovery.