Holy my! For the first time in years, someone wrote 2 decades, OpenBSD Mail Server Bug Allowed Remotely Executing Shell Commands As Root. So I was curious to find it out on my Debian machine:

apt search OpenSMTPD
Ordinamento… Fatto
Ricerca sul testo… Fatto
mblaze/unstable 0.6-1 amd64   utilità UNIX per lavorare con Maildir
opensmtpd/testing,unstable 6.6.2p1-1 amd64   server SMTP sicuro, affidabile, snello e facile da configurare

Well, no other packages refers to it except this mblaze, which is in itself a nice discovery: it offers several commands to handle Maildir

Package: mblaze

Homepage: https://github.com/leahneukirchen/mblaze
Tag: implemented-in::c, interface::commandline, mail::TODO, role::program,
scope::utility, works-with::mail
Download-Size: 125 kB
APT-Sources: http://ftp.it.debian.org/debian unstable/main amd64 Packages
Description: UNIX utilities to deal with Maildir
The mblaze message system is a set of Unix utilities to deal with mail kept in
Maildir folders. It is a classic command line MUA and has no features for
receiving or transferring mail; you are expected to fetch your mail using
fdm(1), getmail(1) offlineimap(1), procmail(1), or similar , and send it using
dma(8), msmtp(1), sendmail(8), as provided by OpenSMTPD, Postfix, or similar.
mblaze expects your mail to reside in Maildir folders.
.
Its design is roughly inspired by MH, the RAND Message Handling System, but it
is a complete implementation from scratch. mblaze operates directly on Maildir
folders and doesn't use its own caches or databases. There is no setup needed
for many uses.
.
mblaze consists of these Unix tools that each do one job:
maddr(1) extract addresses from mail
magrep(1) find mails matching a pattern
mcom(1) compose and send mail
mdeliver(1) deliver messages or import mailboxes
mdirs(1) find Maildir folders
mexport(1) export Maildir folders as mailboxes
mflag(1) change flags (marks) of mail
mflow(1) reflow format=flowed plain text mails
mfwd(1) forward mail
mgenmid(1) generate Message-IDs
mhdr(1) extract mail headers
minc(1) incorporate new mail
mless(1) conveniently read mail in less(1)
mlist(1) list and filter mail messages
mmime(1) create MIME messages
mmkdir(1) create new Maildir
mpick(1) advanced mail filter
mrep(1) reply to mail
mscan(1) generate one-line summaries of mail
msed(1) manipulate mail headers
mseq(1) manipulate mail sequences
mshow(1) render mail and extract attachments
msort(1) sort mail
mthread(1) arrange mail into discussions