The WordPress plugin, WP Database Reset through 3.1, contains a flaw that gave any authenticated user, with minimal permissions, the ability (with a simple wp-admin/admin.php?db-reset-tables[]=users request) to escalate their privileges to administrator while dropping all other users from the table.
https://wpvulndb.com/vulnerabilities/10028
https://wordpress.org/plugins/wordpress-database-reset/#developers