Skull-Splitters PHP Guestbook contains a flaw that allows a remote cross site scripting attack. This flaw exists because the application does not validate the 'url' variable upon submission to the guestbook.php script. This could allow a user to create a specially crafted URL that would execute arbitrary code in a user's browser within the trust relationship between the browser and the server, leading to a loss of integrity.
Upgrade to version 2.75 or higher, as it has been reported to fix this vulnerability. An upgrade is required as there are no known workarounds.
PHP Guestbook is prone to an HTML-injection vulnerability. This issue is due to a lack of proper sanitization of user-supplied input before using it in dynamically generated content.
Attacker-supplied HTML and script code would be executed in the context of the affected website, potentially allowing for the theft of cookie-based authentication credentials. An attacker could also exploit this issue to control how the site is rendered to the user; other attacks are also possible.
This issue can be exploited through use of a web client.