Multiple SQL injection vulnerabilities in PhpWebGallery 1.5.1 and earlier allow remote attackers to execute arbitrary SQL commands via the (1) since, (2) sort_by, and (3) items_number parameters to comments.php, (4) the search parameter to category.php, and (5) image_id parameter to picture.php.  NOTE: it was later reported that the comments.php/sort_by vector also affects 1.7.2 and earlier.