source: https://www.securityfocus.com/bid/8792/info

Geeklog has been reported prone to multiple HTML Injection vulnerabilities.

The issues have been reported to present themselves due to a lack of sufficient sanitization performed on data that is parsed from forum interface form fields. It has been reported that an attacker, who has sufficient privileges to create a forum post, may use the forum form fields as a conduit to inject malicious HTML and script code into dynamic Geeklog content.

The malicious HTML may be rendered in the browser of an unsuspecting user who views the malicious post. Code execution will occur in the context of the affected site. 

<img src="javascript:alert()">

<b style="background-image: url(javascript:alert(document))">test</b>