X.org libXtst before 1.2.3 allows remote X servers to cause a denial of service (infinite loop) via a reply in the (1) XRecordStartOfData, (2) XRecordEndOfData, or (3) XRecordClientDied category without a client sequence and with attached data.
www.openwall.com/lists/oss-security/2016/10/04/2
www.openwall.com/lists/oss-security/2016/10/04/4
www.securityfocus.com/bid/93375
www.securitytracker.com/id/1036945
cgit.freedesktop.org/xorg/lib/libXtst/commit/?id=9556ad67af3129ec4a7a4f4b54a0d59701beeae3
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AFLHX7WNEUXXDAGR324T35L5P6RRR7GE/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RVEUZRHYY3AJEKMFQ4DS7DX3Y2AICFP7/
lists.x.org/archives/xorg-announce/2016-October/002720.html