mysql_install_db in MariaDB 10.4.7 through 10.4.11 allows privilege escalation from the mysql user account to root because chown and chmod are performed unsafely, as demonstrated by a symlink attack on a chmod 04755 of auth_pam_tool_dir/auth_pam_tool. NOTE: this does not affect the Oracle MySQL product, which implements mysql_install_db differently.
https://seclists.org/oss-sec/2020/q1/55
https://github.com/MariaDB/server/commit/9d18b6246755472c8324bf3e20e234e08ac45618