The 404 Solution plugin for WordPress is vulnerable to SQL Injection in all versions up to, and including, 3.1.0 due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query. This is due to improper sanitization of the `filterText` parameter in the `ajaxUpdatePaginationLinks` AJAX action. The sanitization logic can be bypassed by using the sequence `*$/` which becomes `*/` after the `$` character is removed, allowing attackers to escape SQL comment contexts. This makes it possible for authenticated attackers, with administrator-level access and above, to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database via a time-based blind SQL injection technique.