This indicates an attack attempt against a Buffer Overflow vulnerability in Schneider Electric's Accutech Manager.
The vulnerability is caused by a lack of boundary checks when the vulnerable software handles an overly large HTTP request. It allows a remote attacker to execute arbitrary code via a crafted HTTP request.
Schneider Electric Accutech Manager 2.x and prior
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.