The default configuration of SWFUpload in WordPress before 3.5.2 has an unrestrictive security.allowDomain setting, which allows remote attackers to bypass the Same Origin Policy and conduct cross-site scripting (XSS) attacks via a crafted web site.
https://bugzilla.redhat.com/show_bug.cgi?id=976784
http://www.securityfocus.com/bid/60759
http://www.debian.org/security/2013/dsa-2718
http://wordpress.org/news/2013/06/wordpress-3-5-2/