An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. They allow remote IMAP servers to execute arbitrary commands via backquote characters, related to the mailboxes command associated with an automatic subscription.
https://access.redhat.com/errata/RHSA-2018:2526
https://github.com/neomutt/neomutt/commit/e52393740334443ae0206cab2d7caef381646725
https://gitlab.com/muttmua/mutt/commit/185152818541f5cdc059cbff3f3e8b654fc27c1d
https://lists.debian.org/debian-lts-announce/2018/08/msg00001.html
https://neomutt.org/2018/07/16/release
https://security.gentoo.org/glsa/201810-07
https://usn.ubuntu.com/3719-1/
Source: MITRE
Published: 2018-07-17
Updated: 2020-08-24
Type: CWE-78
Base Score: 7.5
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P
Impact Score: 6.4
Exploitability Score: 10
Severity: HIGH
Base Score: 9.8
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 3.9
Severity: CRITICAL