This indicates an attack attempt to exploit a Security Bypass vulnerability in Adobe Flash Player.
Flash Player 10.3.183.7 and earlier.
Flash Player 10.3.183.7 and earlier - network distribution.
Flash Player 10.3.186.6 and earlier for Android.
Flash Player 10.3.183.7 and earlier for Chrome users.
Security Bypass: Remote attackers can bypass security checking of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.