X.org libXrandr before 1.5.1 allows remote X servers to trigger out-of-bounds write operations by leveraging mishandling of reply data.
https://security.gentoo.org/glsa/201704-03
https://lists.x.org/archives/xorg-announce/2016-October/002720.html
https://cgit.freedesktop.org/xorg/lib/libXrandr/commit/?id=a0df3e1c7728205e5c7650b2e6dce684139254a6
http://www.securitytracker.com/id/1036945
http://www.securityfocus.com/bid/93373