Describe CVE-2021-4450.
What is CVE-2021-4450?
The Post Grid plugin for WordPress is vulnerable to blind SQL Injection via post metadata in versions up to, and including, 2.1.12 due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query.  This makes it possible for authenticated attackers with contributor-level permissions and above to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database..