The decode_init function in kmvc.c in libavcodec in FFmpeg before 0.10 and in Libav 0.5.x before 0.5.9, 0.6.x before 0.6.6, 0.7.x before 0.7.6, and 0.8.x before 0.8.1 allows remote attackers to cause a denial of service (application crash) and possibly execute arbitrary code via a large palette size in a KMVC encoded file.