CVE 2012-0287

Cross-site scripting (XSS) vulnerability in wp-comments-post.php in WordPress 3.3.x before 3.3.1, when Internet Explorer is used, allows remote attackers to inject arbitrary web script or HTML via the query string in a POST operation that is not properly handled by the "Duplicate comment detected" feature.

See the CVE page on Mitre.org for more details.