This indicates an attack attempt to exploit a Code Injection vulnerability in Citrix NetScaler SD-WAN devices.
The vulnerability is due to an error in the application when handling a crafted HTTP POST request. It may allow remote attackers to execute arbitrary code on vulnerable systems, via a crafted HTTP POST request.
Citrix NetScaler SD-WAN devices v188.8.131.52.561201 and previous version
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.