Endless recursion exists in xkbcomp/expr.c in xkbcommon and libxkbcommon before 0.8.1, which could be used by local attackers to crash xkbcommon users by supplying a crafted keymap file that triggers boolean negation.
"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2018-15853.json"