A flaw was found in mupdf 1.18.0. Double free of object during linearization may lead to memory corruption and other potential consequences.
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=703366
http://git.ghostscript.com/?p=mupdf.git%3Bh=cee7cefc610d42fd383b3c80c12cbc675443176a