In the IMAP Server in Dovecot 2.3.3 through 2.3.5.2, the submission-login service crashes when the client disconnects prematurely during the AUTH command.
https://www.dovecot.org/security.html
https://www.dovecot.org/download.html
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00026.html
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00024.html