Gallery by BestWebSoft <= 4.7.9 - Authenticated (Editor+) SQL Injection via Gallery Image Order Array Keys

The Gallery by BestWebSoft plugin for WordPress is vulnerable to SQL Injection via the '_gallery_order_{post_id}' parameter array keys in all versions up to, and including, 4.7.9. This is due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query. The `gllr_save_postdata()` function stores unsanitized array keys from `$_POST` directly into post meta, which are later used in SQL queries without prepared statements. This makes it possible for authenticated attackers, with Editor-level access and above, to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database.