A double free in cleanup_index in index.c in Halibut 1.2 allows an attacker to cause a denial of service or possibly have other unspecified impact via a crafted text document.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-29577
https://carteryagemann.com/halibut-case-study.html#poc-halibut-winhelp-df