An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. imap/message.c has a stack-based buffer overflow for a FETCH response with a long RFC822.SIZE field.
https://www.debian.org/security/2018/dsa-4277
https://usn.ubuntu.com/3719-3/
https://usn.ubuntu.com/3719-1/
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/3287534daa3beac68e2e83ca4b4fe8a3148ff870
https://github.com/neomutt/neomutt/commit/1b0f0d0988e6df4e32e9f4bf8780846ea95d4485