The ff_free_picture_tables function in libavcodec/mpegpicture.c in Libav 12.2 allows remote attackers to cause a denial of service (heap-based buffer overflow and application crash) or possibly have unspecified other impact via a crafted file, related to vc1_decode_i_blocks_adv.
https://lists.debian.org/debian-lts-announce/2019/01/msg00006.html