In cloud-init through 19.4, rand_user_password in cloudinit/config/cc_set_passwords.py has a small default pwlen value, which makes it easier for attackers to guess passwords.
https://lists.debian.org/debian-lts-announce/2020/02/msg00021.html
https://github.com/canonical/cloud-init/pull/189
https://bugs.launchpad.net/ubuntu/+source/cloud-init/+bug/1860795
http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00042.html