The Read More & Accordion plugin for WordPress is vulnerable to time-based blind SQL Injection via the 'orderby' parameter in all versions up to, and including, 3.5.7. This is due to the use of esc_sql() without surrounding the value in quotes in an ORDER BY clause inside the getAllDataByLimit() and getAccordionAllDataByLimit() functions in ReadMoreData.php. The user-supplied $_GET['orderby'] value is only processed through esc_attr() (an HTML-escaping function) before being passed to these data