gtk-vnc before 0.7.0 does not properly check boundaries of subrectangle-containing tiles, which allows remote servers to execute arbitrary code via the src x, y coordinates in a crafted (1) rre, (2) hextile, or (3) copyrect tile.
www.openwall.com/lists/oss-security/2017/02/03/5
www.openwall.com/lists/oss-security/2017/02/05/5
www.securityfocus.com/bid/96016
access.redhat.com/errata/RHSA-2017:2258
bugzilla.gnome.org/show_bug.cgi?id=778048
git.gnome.org/browse/gtk-vnc/commit/?id=ea0386933214c9178aaea9f2f85049ea3fa3e14a
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LGPQ5MQR6SN4DYTEFACHP2PP5RR26KYK/