MediaWiki before 1.19.24, 1.2x before 1.23.9, and 1.24.x before 1.24.2 does not properly handle when the Zend interpreter xml_parse function does not expand entities, which allows remote attackers to inject arbitrary web script or HTML via a crafted SVG file.
https://security.gentoo.org/glsa/201510-05
https://phabricator.wikimedia.org/T88310
https://lists.wikimedia.org/pipermail/mediawiki-announce/2015-March/000175.html
http://www.securityfocus.com/bid/73477
http://www.openwall.com/lists/oss-security/2015/04/07/3
http://www.openwall.com/lists/oss-security/2015/04/01/1
http://www.mandriva.com/security/advisories?name=MDVSA-2015:200