*** This bug is a security vulnerability *** Private security bug reported: Hello, because we got some spam from outside, but with email-adress of a list- member lately, we found after an investigation that the E-Mail Header From: "memberuseremail@" <memberuserdomain.tld somerandomspamemail.tld> will be accepted by mailman and posted to the list. So if the spammer knows a valid member-emailadress it is possible to send emails to the list. I don't know if this is fixed already and i have to poke the ubuntu team instead. Versions: Ubuntu 16.04 LTS Mailman Version: 1:2.1.20-1ubuntu0.1 Postfix Version: 3.1.0-3 ** Affects: mailman Importance: Undecided Status: New ** Tags: email sender -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/1721746 Title: [If member-email known] Malformed "From:" header accepted -> anyone can post to list. To manage notifications about this bug go to: https://bugs.launchpad.net/mailman/+bug/1721746/+subscriptions