CVE-2019-9721

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2019-03-12 · updated 2026-06-17
Weakness: CWE-125

Description

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 handle_open_brace in libavcodec/htmlsubtitles.c has a complex format argument to sscanf.

Affected products

Canonical Ubuntu Linux: 18.04, 18.10, 19.04
FFmpeg: 3.2, 4.1

References

http://www.securityfocus.com/bid/107384
https://git.ffmpeg.org/gitweb/ffmpeg.git/commit/894995c41e0795c7a44f81adc4838dedc3932e65
https://github.com/FFmpeg/FFmpeg/commit/273f2755ce8635d42da3cde0eeba15b2e7842774
https://usn.ubuntu.com/3967-1/
http://www.securityfocus.com/bid/107384
https://git.ffmpeg.org/gitweb/ffmpeg.git/commit/894995c41e0795c7a44f81adc4838dedc3932e65
https://github.com/FFmpeg/FFmpeg/commit/273f2755ce8635d42da3cde0eeba15b2e7842774
https://usn.ubuntu.com/3967-1/

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