An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. pop.c mishandles a zero-length UID.
https://www.debian.org/security/2018/dsa-4277
https://usn.ubuntu.com/3719-3/
https://security.gentoo.org/glsa/201810-07
https://neomutt.org/2018/07/16/release
https://lists.debian.org/debian-lts-announce/2018/08/msg00001.html
https://gitlab.com/muttmua/mutt/commit/e154cba1b3fc52bb8cb8aa846353c0db79b5d9c6
https://github.com/neomutt/neomutt/commit/93b8ac558752d09e1c56d4f1bc82631316fa9c82