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 22.214.171.124 and earlier versions
Adobe Flash Player 126.96.36.199 and earlier 13.x versions
Adobe Flash Player 188.8.131.521 and earlier versions for Linux
Adobe AIR desktop runtime 184.108.40.2063 and earlier versions
Adobe AIR SDK 220.127.116.112 and earlier versions
Adobe AIR SDK & Compiler 18.104.22.1682 and earlier versions
Adobe AIR 22.214.171.1243 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.