Mutt is vulnerable to TLS response injection. A STARTTLS buffering issue that affects IMAP, SMTP, and POP3 when a server sends a begin TLS
response causes the client to read additional data (e.g. from a man-in-the-middle attacker) and evaluates it in a TLS context, aka response injection.
lists.mutt.org/pipermail/mutt-announce/Week-of-Mon-20200615/000023.html
lists.opensuse.org/opensuse-security-announce/2020-06/msg00064.html
lists.opensuse.org/opensuse-security-announce/2020-06/msg00070.html
www.mutt.org/
github.com/neomutt/neomutt/commit/fb013ec666759cb8a9e294347c7b4c1f597639cc
github.com/neomutt/neomutt/releases/tag/20200619
gitlab.com/muttmua/mutt/-/commit/c547433cdf2e79191b15c6932c57f1472bfb5ff4
gitlab.com/muttmua/mutt/-/issues/248
lists.debian.org/debian-lts-announce/2020/06/msg00039.html
lists.debian.org/debian-lts-announce/2020/06/msg00040.html
lists.fedoraproject.org/archives/list/[email protected]/message/EFMEILCBKMZRRZDMUGWLVN4PQQ4VTAZE/
lists.fedoraproject.org/archives/list/[email protected]/message/K3LXFVPTLK4PNHL6MPKJNJQJ25CH7GLQ/
security.gentoo.org/glsa/202007-57
usn.ubuntu.com/4403-1/
www.debian.org/security/2020/dsa-4707
www.debian.org/security/2020/dsa-4708