The quoteblock function in markdown.c in libmarkdown.a in DISCOUNT 2.2.3a allows remote attackers to cause a denial of service (heap-based buffer over-read) via a crafted file.
https://github.com/Orc/discount/issues/189#issuecomment-397541501
https://lists.debian.org/debian-lts-announce/2018/09/msg00009.html