GNU Mailman is vulnerable to content injection. An attacker is able to inject arbitrary content into the application via the Cgi/private.py
private archive login page.
lists.opensuse.org/opensuse-security-announce/2020-10/msg00047.html
lists.opensuse.org/opensuse-security-announce/2020-10/msg00063.html
bugs.launchpad.net/mailman/+bug/1877379
lists.debian.org/debian-lts-announce/2020/06/msg00036.html
lists.debian.org/debian-lts-announce/2020/07/msg00007.html
security-tracker.debian.org/tracker/CVE-2020-15011
usn.ubuntu.com/4406-1/
www.debian.org/security/2021/dsa-4991