In MuPDF 1.13.0, there is an infinite loop in the fz_skip_space function of the pdf/pdf-xref.c file. A remote adversary could leverage this vulnerability to cause a denial of service via a crafted pdf file.
https://lists.debian.org/debian-lts-announce/2021/09/msg00013.html
https://bugs.ghostscript.com/show_bug.cgi?id=699271
http://www.ghostscript.com/cgi-bin/findgit.cgi?2e43685dc8a8a886fc9df9b3663cf199404f7637