This indicates an attack attempt to exploit a Remote Code Execution vulnerability in Zabbix.
The vulnerability is due to a design flaw when the vulnerable software handles a crafted HTTP request. A remote attacker may be able to exploit this to execute arbitrary code within the context of the application, via a crafted HTTP request.
Zabbix 2.0.9 and prior
System Compromise: Remote attackers can gain control of vulnerable systems.
Currently, we are unaware of any vendor supplied patch for this issue.