wp-includes/http.php in WordPress before 3.7.5, 3.8.x before 3.8.5, 3.9.x before 3.9.3, and 4.x before 4.0.1 allows remote attackers to conduct server-side request forgery (SSRF) attacks by referring to a 127.0.0.0/8 resource.
https://wordpress.org/news/2014/11/wordpress-4-0-1/
https://core.trac.wordpress.org/changeset/30444
http://www.securitytracker.com/id/1031243
http://www.mandriva.com/security/advisories?name=MDVSA-2014:233
http://www.debian.org/security/2014/dsa-3085