This indicates an attack attempt to exploit a Remote Code Execution vulnerability in Adobe Flash Player.
The vulnerability is due to an error when the vulnerable software handles a maliciously crafted SWF file. A remote attacker may be able to exploit this to execute arbitrary code within the context of the application, via a crafted SWF file.
Adobe Flash Player 18.104.22.1687 and earlier versions
Adobe Flash Player 22.214.171.1242 and earlier 13.x versions
Adobe Flash Player 126.96.36.1998 and earlier versions for Linux
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.