source: https://www.securityfocus.com/bid/22534/info

WordPress is prone to a cross-site scripting vulnerability because the application fails to properly sanitize user-supplied input.

An attacker may leverage this issue to execute arbitrary script code in the browser of an unsuspecting user. This may help the attacker steal cookie-based authentication credentials and launch other attacks. 

http://www.example.com/wordpress/wp-admin/templates.php?action=update&file=<script>alert("Faille Xss")</script>&submit=Update+File+%C2%BB