In Artifex MuPDF 1.12.0, the pdf_read_new_xref function in pdf/pdf-xref.c allows remote attackers to cause a denial of service (segmentation violation and application crash) via a crafted pdf file.
https://www.debian.org/security/2018/dsa-4334
https://security.gentoo.org/glsa/201811-15
https://lists.debian.org/debian-lts-announce/2019/06/msg00027.html