Team ENVY, a Security Research TEAM has found a flaw that allows for a remote code execution on the NVR. If an attacker does not enter any value for a specific URL parameter, NULL pointer references will occur and the NVR will reboot. The manufacturer has released patch firmware for the flaw, please refer to the manufacturers report for details and workarounds.
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.