The vmnc decoder in the gstreamer does not initialize the render canvas, which allows remote attackers to obtain sensitive information as demonstrated by thumbnailing a simple 1 frame vmnc movie that does not draw to the allocated render canvas.
www.openwall.com/lists/oss-security/2016/11/18/12
www.openwall.com/lists/oss-security/2016/11/18/13
www.securityfocus.com/bid/94423
access.redhat.com/errata/RHSA-2017:2060
bugzilla.gnome.org/show_bug.cgi?id=774533
cgit.freedesktop.org/gstreamer/gst-plugins-bad/commit/gst/vmnc/vmncdec.c?id=4cb1bcf1422bbcd79c0f683edb7ee85e3f7a31fe
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UM7IXFGHV66KNWGWG6ZBDNKXD2UJL2VQ/
scarybeastsecurity.blogspot.de/2016/11/0day-poc-risky-design-decisions-in.html
security.gentoo.org/glsa/201705-10