libavcodec/webp.c in FFmpeg before 2.8.12, 3.0.x before 3.0.8, 3.1.x before 3.1.8, 3.2.x before 3.2.5, and 3.3.x before 3.3.1 does not ensure that pix_fmt is set, which 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 the vp8_decode_mb_row_no_filter and pred8x8_128_dc_8_c functions.
The cdxl_decode_frame function in libavcodec/cdxl.c in FFmpeg 2.8.x before 2.8.12, 3.0.x before 3.0.8, 3.1.x before 3.1.8, 3.2.x before 3.2.5, and 3.3.x before 3.3.1 does not exclude the CHUNKY format, which 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.
FFmpeg before 2017-03-05 has an out-of-bounds write caused by a heap-based buffer overflow related to the ff_h264_slice_context_init function in libavcodec/h264dec.c.