Ansible "User" module leaks any data which is passed on as a parameter to ssh-keygen. This could lean in undesirable situations such as passphrases credentials passed as a parameter for the ssh-keygen executable. Showing those credentials in clear text form for every user which have access just to the process list.
https://www.debian.org/security/2019/dsa-4396
https://usn.ubuntu.com/4072-1/
https://lists.debian.org/debian-lts-announce/2018/11/msg00012.html
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16837
https://access.redhat.com/security/cve/cve-2018-16837
https://access.redhat.com/errata/RHSA-2018:3505
https://access.redhat.com/errata/RHSA-2018:3463
https://access.redhat.com/errata/RHSA-2018:3462
https://access.redhat.com/errata/RHSA-2018:3461
https://access.redhat.com/errata/RHSA-2018:3460
http://www.securityfocus.com/bid/105700
http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00020.html
http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00077.html
http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00021.html