This indicates an attack attempt to exploit a Code Injection Vulnerability in Arris VAP2500.
The vulnerability is due to a design error while handling user authentication. A remote attacker could exploit this to execute arbitrary code within the context of the application, via a crafted HTTP request without authentication.
ARRIS VAP2500 FW 08.40 or prior
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.