Multiple SQL injection vulnerabilities in Joomla! 1.5.x before 1.5.22 allow remote attackers to execute arbitrary SQL commands via (1) the filter_order parameter in a com_weblinks category action to index.php, (2) the filter_order_Dir parameter in a com_weblinks category action to index.php, or (3) the filter_order_Dir parameter in a com_messages action to administrator/index.php.