Ah, it looks like this is actually a bug in mailman3 after all - but the change in apache2 has exposed it.
I'll file a bug report there. Thread here: https://lists.mailman3.org/archives/list/mailman- [email protected]/thread/JSLTGUQDWRGQTOZWUKIOSDJLJSDYMSUC/ -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1945710 Title: mailman3 has broken since apache2 security upgrade To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apache2/+bug/1945710/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
