This indicates an attack attempt to exploit an Arbitrary File Upload vulnerability in D-Link Central WiFiManager.
The vulnerability is due to insufficient sanitizing of user supplied inputs in the application when handling a crafted HTTP request. An unauthenticated remote attacker may be able to exploit this to upload an arbitrary file, leading to a possible code execution condition.
D-Link Central WiFiManager version 1.03
System Compromise: Remote attackers can execute arbitrary code on vulnerable systems.
Apply the most recent upgrade or patch from the vendor.