Ansible 2.5 prior to 2.5.5, and 2.4 prior to 2.4.5, do not honor the no_log task flag for failed tasks. When the no_log flag has been used to protect sensitive data passed to a task from being logged, and that task does not run successfully, Ansible will expose sensitive data in log files and on the terminal of the user running Ansible.
https://www.debian.org/security/2019/dsa-4396
https://usn.ubuntu.com/4072-1/
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10855
https://access.redhat.com/errata/RHSA-2019:0054
https://access.redhat.com/errata/RHSA-2018:2585
https://access.redhat.com/errata/RHSA-2018:2184
https://access.redhat.com/errata/RHSA-2018:2079
https://access.redhat.com/errata/RHSA-2018:2022
https://access.redhat.com/errata/RHSA-2018:1949