(1) ApiBlock.php (2) ApiCreateAccount.php (3) ApiLogin.php (4) ApiMain.php (5) ApiQueryDeletedrevs.php (6) ApiTokens.php and (7) ApiUnblock.php in includes/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 allow remote attackers to obtain CSRF tokens and bypass the cross-site request forgery (CSRF) protection mechanism via a JSONP request to wiki/api.php.