:seko has discovered a vulnerability in Big Blue Guestbook, which can be exploited by malicious people to conduct cross-site scripting attacks.Input passed to the "comments" parameter in signguestbook.php is not properly sanitised before being stored. This can be exploited to insert arbitrary HTML and script code, which can be executed in a user’s browser session in context of an affected site when the guestbook is viewed.Solution:Edit the source code to ensure that input is properly sanitised.Provided and/or discovered by:seko

Original post by kapil