_XcursorThemeInherits in library.c in libXcursor before 1.1.15 allows remote attackers to cause denial of service or potentially code execution via a one-byte heap overflow.
https://usn.ubuntu.com/3729-1/
https://lists.debian.org/debian-lts-announce/2018/08/msg00016.html
https://cgit.freedesktop.org/xorg/lib/libXcursor/commit/?id=897213f36baf6926daf6d192c709cf627aa5fd05
https://bugs.freedesktop.org/show_bug.cgi?id=90857