Unchecked NULL pointer usage in resolve_keysym in xkbcomp/parser.y in xkbcommon before 0.8.2 could be used by local attackers to crash (NULL pointer dereference) the xkbcommon parser by supplying a crafted keymap file, because a map access attempt can occur for a map that was never created.
https://usn.ubuntu.com/3786-2/
https://usn.ubuntu.com/3786-1/
https://security.gentoo.org/glsa/201810-05
https://lists.freedesktop.org/archives/wayland-devel/2018-August/039243.html
https://github.com/xkbcommon/libxkbcommon/commit/a8ea7a1d3daa7bdcb877615ae0a252c189153bd2