list.php in DigiOz Guestbook before 1.7.1 allows remote attackers to obtain sensitive information via a non-numeric page parameter, which displays the installation path in the resulting error message.
https://exchange.xforce.ibmcloud.com/vulnerabilities/30067
http://www.securityfocus.com/archive/1/450826/30/0/threaded
http://www.netvigilance.com/advisory0006