This indicates an attack attempt against a remote code execution vulnerability in Adobe's Flash Player.
The vulnerability is caused when the Flash player attempts to access embedded Actionscript objects that have not been properly instantiated. An attacker may exploit this issue to execute arbitrary code in the context of the affected application.
Adobe Flash Player 18.104.22.168 and earlier versions
System Compromise: Remote attackers can gain control of vulnerable systems.
Refer to the vendor's website for suggested workaround.