A denial of service in the subtitle decoder in FFmpeg 3.2 and 4.1 allows attackers to hog the CPU via a crafted video file in Matroska format, because handleopenbrace in libavcodec/htmlsubtitles.c has a complex format argument to sscanf.
[
{
"source": "https://github.com/ffmpeg/ffmpeg/commit/273f2755ce8635d42da3cde0eeba15b2e7842774",
"target": {
"function": "ff_htmlmarkup_to_ass",
"file": "libavcodec/htmlsubtitles.c"
},
"digest": {
"function_hash": "51195086334001458191859035190219042570",
"length": 3610.0
},
"deprecated": false,
"signature_type": "Function",
"id": "CVE-2019-9721-1e4b4ede",
"signature_version": "v1"
},
{
"source": "https://github.com/ffmpeg/ffmpeg/commit/273f2755ce8635d42da3cde0eeba15b2e7842774",
"target": {
"file": "libavcodec/htmlsubtitles.c"
},
"digest": {
"line_hashes": [
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"114335331683057061847747733341231002884",
"52182576610393413327815494532710655027",
"151988408299784471571915177291850664201",
"143530476180291881434987183528048468203",
"20671168889515778463202263099394878314",
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"244888744203267073148994254791264550488"
],
"threshold": 0.9
},
"deprecated": false,
"signature_type": "Line",
"id": "CVE-2019-9721-efb6ae89",
"signature_version": "v1"
}
]