cloud-init through 19.4 relies on Mersenne Twister for a random password, which makes it easier for attackers to predict passwords, because rand_str in cloudinit/util.py calls the random.choice function.
https://github.com/canonical/cloud-init/pull/204
https://bugs.launchpad.net/ubuntu/+source/cloud-init/+bug/1860795
https://lists.debian.org/debian-lts-announce/2020/02/msg00021.html
http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00042.html
Source: MITRE
Published: 2020-02-05
Updated: 2021-12-22
Type: CWE-330
Base Score: 2.1
Vector: AV:L/AC:L/Au:N/C:P/I:N/A:N
Impact Score: 2.9
Exploitability Score: 3.9
Severity: LOW
Base Score: 5.5
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Impact Score: 3.6
Exploitability Score: 1.8
Severity: MEDIUM