[Mailman-Users] Mailman "host_name" security issue?

Hello,

I haven't found this at Google so maybe nobody has thought about it yet.

I use Postfix with postfix-to-mailman.py and no alias setup. I also use
several domains. Some of them are in the mailman transport table and only
used for mailing lists. (whatever at lists.domain.foo)

If you have some domains used by lists, and some used for normal email, what
happens if you have

a mailinglist called abc at lists.domain.com
an user account called abc at domain.com

and the list admin changes "host_name" from lists.domain.com to domain.com?

I would suspect all mail to whatever at domain.com to bounce, and mail to
abc at domain.com to be delivered to the list, instead of the user.


Am I correct? If not, is this a security issue at all?