Cross-site scripting (XSS) vulnerability in guestbook.php in phpBook 1.46 allows remote attackers to inject arbitrary web script or HTML via the admin parameter.
phpBook 2.1.0 allows remote attackers to obtain sensitive information via a direct request to a .php file, which reveals the installation path in an error message, as demonstrated by doc/updatesmilies1.50-1.60.php and certain other files.