source: https://www.securityfocus.com/bid/15990/info

LiveJournal is prone to an HTML injection vulnerability. This issue is due to a failure in the application to properly sanitize 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 Web site, potentially allowing for 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. 

Example HTML exploit code has been provided:

<span style="background:url('javas\cript:(function x(){alert("boo")})();');">test</span>