Artifex MuPDF before 1.18.0 has a heap based buffer over-write when parsing JBIG2 files allowing attackers to cause a denial of service.
https://www.debian.org/security/2020/dsa-4794
https://security.gentoo.org/glsa/202105-30
https://lists.debian.org/debian-lts-announce/2021/03/msg00012.html
https://bugs.ghostscript.com/show_bug.cgi?id=702937
http://git.ghostscript.com/?p=mupdf.git%3Ba=commit%3Bh=af1e390a2c7abceb32676ec684cd1dbb92907ce8