Heap-based buffer overflow in the CGIFCodec::GetPacketBuffer function in datatype/image/gif/common/gifcodec.cpp in RealNetworks RealPlayer 10; RealPlayer 10.5 6.0.12.1040 through 6.0.12.1741; RealPlayer 11 11.0.0 through 11.0.4; RealPlayer Enterprise; Mac RealPlayer 10, 10.1, and 11.0; Linux RealPlayer 10; and Helix Player 10.x allows remote attackers to execute arbitrary code via a GIF file with crafted chunk sizes that trigger improper memory allocation.