The Percona Server 5.6.44-85.0-1 packages for Debian and Ubuntu suffered an issue where the server would reset the root password to a blank value upon an upgrade. This was fixed in 5.6.44-85.0-2.

mariadb: Replication in sql/event_data_objects.cc occurs before ACL checks

sql/event_data_objects.cc in MariaDB before 10.1.30 and 10.2.x before 10.2.10 and Percona XtraDB Cluster before 5.6.37-26.21-3 and 5.7.x before 5.7.19-29.22-3 allows remote authenticated users with SQL access to bypass intended access restrictions and replicate data definition language (DDL) statements to cluster nodes by leveraging incorrect ordering of DDL replication and ACL checking.