CVE 2013-5738

The get_allowed_mime_types function in wp-includes/functions.php in WordPress before 3.6.1 does not require the unfiltered_html capability for uploads of .htm and .html files, which might make it easier for remote authenticated users to conduct cross-site scripting (XSS) attacks via a crafted file.

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