libXcursor before 1.1.15 has various integer overflows that could lead to heap buffer overflows when processing malicious cursors, e.g., with programs like GIMP. It is also possible that an attack vector exists against the related code in cursor/xcursor.c in Wayland through 1.14.0.
security.cucumberlinux.com/security/details.php?id=156
www.openwall.com/lists/oss-security/2017/11/28/6
www.ubuntu.com/usn/USN-3501-1
bugzilla.suse.com/show_bug.cgi?id=1065386
cgit.freedesktop.org/wayland/wayland/commit/?id=5d201df72f3d4f4cb8b8f75f980169b03507da38
cgit.freedesktop.org/xorg/lib/libXcursor/commit/?id=4794b5dd34688158fb51a2943032569d3780c4b8
lists.debian.org/debian-lts-announce/2017/12/msg00002.html
lists.freedesktop.org/archives/wayland-devel/2017-November/035979.html
marc.info/?l=freedesktop-xorg-announce&m=151188036018262&w=2
security.gentoo.org/glsa/201801-04
usn.ubuntu.com/3622-1/
www.debian.org/security/2017/dsa-4059