This indicates an attack attempt to exploit a remote Code Execution vulnerability in Adobe Flash Player.
The vulnerability is due to a type confusion error when the vulnerable software handles a maliciously crafted MP4 file. A remote attacker may be able to exploit this to execute arbitrary code within the context of the application, via a crafted MP4 file.
Adobe Flash Player 184.108.40.206 and earlier versions
Adobe Flash Player 220.127.116.11 and earlier 13.x versions
Adobe Flash Player 18.104.22.1681 and earlier versions for Linux
Adobe AIR desktop runtime 22.214.171.1243 and earlier versions
Adobe AIR SDK 126.96.36.1992 and earlier versions
Adobe AIR SDK & Compiler 188.8.131.522 and earlier versions
Adobe AIR 184.108.40.2063 and earlier versions for Android
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.