This indicates an attack attempt to exploit a Buffer Overflow vulnerability in Dlink Routers.
The vulnerability is due to insufficient sanitization of user supplied inputs in the application. A remote attacker may be able to exploit this to execute arbitrary command within the context of the application, via a crafted request.
Dlink DIR 8XX routers before v1.12
System Compromise: Remote attackers can gain control of vulnerable systems.
update router firmware to latest version.