[Mailman-Users] How hard is it to spoof an email?

[Jp Possenti]

How hard would it be for someone to maliciously start sending all the users
in my list emails or start deleting people from it by sending bounce errors
or by spoofing the admin email and start emailing everyone on the list?
Is this a common problem, or is mailman secure about it? What are some ways
to help avoid any problems?
Please explain carefully and with plenty of details as I am still figuring
things out.
 
Kind regards,
 
Jp