There have been many Exim bugs like this, why are people still running it? It's like the modern day sendmail.
https://www.cvedetails.com/vendor/10919/Exim.html 12 RCE CVE entries since the CVE system started.
https://www.cvedetails.com/vendor/10919/Exim.html 12 RCE CVE entries since the CVE system started.
It also can do things that other MTAs can't do at all, again due to it being a monolith.
Postfix for example is made out of a string of independent programs that pass mail to one another. Once a program has an email that program can only deal with the email itself or pass it along to the next program. That limits what can be done with that email and makes the configuration harder to understand.
(I don't send e-mail to the outside or listen for any outside e-mail, so the choice of MTA is irrelevant to me as long as the system can still send over localhost to /var/mail/$USER.)
Interestingly, other panels seem to use other SMTP servers: https://www.liquidweb.com/kb/comparison-of-the-four-major-se...
Disclaimer: just reading about opensmtp, I'm using postfix
Exim is an SMTP server (MTA), not an email client (MUA).
It has "enterprise" in the name though so it's unlikely to be very robust or secure.
Otherwise, business opportunity for other language communities.
Thunderbird is an MUA and is not a substitute for an MTA like Exim.
Flexibility, mostly. It's configuration file includes a programming language of sorts, which means most things can be done write resorting to plugins or worse - having to write one.