This indicates an attack attempt to exploit a Remote Command Injection vulnerability in Polycom HDX servies.
The vulnerability is due to an error when the vulnerable software attempts to handle a maliciously crafted request. An attacker can exploit this by injecting a command onto a request to execute arbitrary command within the context of the application.
Polycom HDX 2.1.11 hotfix 1 and prior version
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.