The RV20 codec in RealNetworks RealPlayer 11.x, 14.x, and 15.x before 15.02.71, and RealPlayer SP 1.0 through 1.1.5, does not properly handle the frame size array, which allows remote attackers to execute arbitrary code via a crafted RV20 RealVideo video stream.
http://www.securityfocus.com/bid/51884
http://service.real.com/realplayer/security/02062012_player/en/