Secunia Security Advisory – A vulnerability has been discovered in YaBB, which can be exploited by malicious people to conduct script insertion attacks. The vulnerability is caused due to an input validation error in the attachment upload handling. This can be exploited to execute arbitrary HTML and script code in a user’s browser session in context of an affected site by attaching a malicious HTML document with a valid file extension (e.g. .gif) in a post. Successful exploitation requires that the attachment is accessed directly in the Microsoft Internet Explorer browser (e.g. by opening an attachment in a post). Some other issues which may be security related have also been reported. The vulnerability has been confirmed in version 2.0. Prior versions may also be affected.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/41423/sa17411.txt
Source: https://packetstormsecurity.com/files/41423/Secunia-Security-Advisory-17411.html