In Libav through 11.11 and 12.x through 12.1, the smacker_decode_tree function in libavcodec/smacker.c does not properly restrict tree recursion, which allows remote attackers to cause a denial of service (bitstream.c:build_table() out-of-bounds read and application crash) via a crafted Smacker stream. https://nvd.nist.gov/vuln/detail/CVE-2017-16803
