CVE-2019-9721: Canonical Ubuntu Linux

Medium severity, CVSS 6.5. EPSS: 1.4% chance of exploitation in the next 30 days.

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: version 18.04 only; version 18.10 only; version 19.04 only
• Ffmpeg Ffmpeg: version 3.2 only; version 4.1 only

Published 2019-03-12. Last modified 2026-06-17.