Multiple cross-site scripting vulnerabilities in signed.php in Hinton Design phphg Guestbook 1.2 allow remote attackers to inject arbitrary web script or HTML via the (1) location, (2) website, or (3) message parameter.

check.php in Hinton Design phphg Guestbook 1.2 does not check the user password when authenticating via cookies, which allows remote attackers to gain unauthorized access.

Multiple SQL injection vulnerabilities in Hinton Design phphg Guestbook 1.2 allow remote attackers to execute arbitrary SQL commands via the (1) username parameter to check.php or the id parameter to (2) admin/edit_smilie.php, (3) admin/add_theme.php, (4) admin/ban_ip.php, (5) admin/add_lang.php, or (6) admin/edit_filter.php.