/etc/security/user_map.conf gets overwritten when updating MariaDB-server RPM package from our community repository. Offending package:

[root@mariadb11 assen.totin]# rpm -q MariaDB-server
MariaDB-server-10.4.12-1.el7.centos.x86_64

Hit this on two running systems. This is quite bad, because this file contains user mapping for PAM-based logins. The default file is empty (everything is commented out), so all configured mappings are lost on upgrade. This file must be labelled "config noreplace" in the RPM spec file which will prevent RPM from touching the file if the currently existing one has any alterations.

It is quite possible that all other released packages have this issue, so I'd check all RPM packages built with the same/similar spec file in all supported mainlines. If they contain the same bug, they can be repackaged with an increase of the release number only (as this is change in packaging, not in MariaDB version).