The gmc_mmx function in libavcodec/x86/mpegvideodsp.c in FFmpeg 2.3 and 3.4 does not properly validate widths and heights, which allows remote attackers to cause a denial of service (integer signedness error and out-of-array read) via a crafted MPEG file.
The VC-2 Video Compression encoder in FFmpeg 3.0 and 3.4 allows remote attackers to cause a denial of service (out-of-bounds read) because of incorrect buffer padding for non-Haar wavelets, related to libavcodec/vc2enc.c and libavcodec/vc2enc_dwt.c.