Provide references for CVE-2019-9721.
Where can I find more information about CVE-2019-9721?
References are available at: http://www.securityfocus.com/bid/107384, https://git.ffmpeg.org/gitweb/ffmpeg.git/commit/894995c41e0795c7a44f81adc4838dedc3932e65, https://usn.ubuntu.com/3967-1/, https://github.com/FFmpeg/FFmpeg/commit/273f2755ce8635d42da3cde0eeba15b2e7842774.