In DjVuLibre 3.5.27, the sorting functionality (aka GArrayTemplate<TYPE>::sort) allows attackers to cause a denial-of-service (application crash due to an Uncontrolled Recursion) by crafting a PBM image file that is mishandled in libdjvu/GContainer.h.
https://www.debian.org/security/2021/dsa-5032
https://usn.ubuntu.com/4198-1/
https://sourceforge.net/p/djvu/djvulibre-git/ci/e15d51510048927f172f1bf1f27ede65907d940d/
https://sourceforge.net/p/djvu/bugs/299/
https://security.gentoo.org/glsa/202007-36
https://lists.debian.org/debian-lts-announce/2021/05/msg00022.html
https://lists.debian.org/debian-lts-announce/2019/08/msg00036.html
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00087.html
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00086.html