This indicates an attack attempt to exploit a Command Execution vulnerability in multiple Grandstream devices.
The vulnerability is caused by an error when the vulnerable software handles a malicious HTTP request. A remote attacker may be able to exploit this to execute arbitrary code on vulnerable systems.
Grandstream GAC2500 22.214.171.124
Grandstream GXP2200 126.96.36.199
Grandstream GVC3202 188.8.131.52
Grandstream GXV3275 before 184.108.40.206 Beta
Grandstream GXV3240 before 220.127.116.11 Beta
System Compromise: Remote attackers can gain control of vulnerable system.
Apply the most recent upgrade or patch from the vendor.