In FFmpeg 4.0.1, due to a missing check of a profile value before setting it, the ff_mpeg4_decode_picture_header function in libavcodec/mpeg4videodec.c may trigger a NULL pointer dereference while converting a crafted AVI file to MPEG4, leading to a denial of service. https://nvd.nist.gov/vuln/detail/CVE-2018-13301