MediaWiki Improper Neutralization of Input During Web Page Generation (Cross-site Scripting) Vulnerability - CVE-2013-4303
includes/libs/IEUrlExtension.php in the MediaWiki API in MediaWiki 1.19.x before 1.19.8 1.20.x before 1.20.7 and 1.21.x before 1.21.2 does not properly detect extensions when there are an even number of quot.quot (period) characters in a string which allows remote attackers to conduct cross-site scripting (XSS) attacks via the siprop parameter in a query action to wiki/api.php.