Discuz! X3.4 allows XSS via admin.php because admincp/admincpsetting.php and template\default\common\footer.htm mishandles statcode field from third-party stats code.
Discuz!ML 3.2 through 3.4 allows remote attackers to execute arbitrary PHP code via a modified language cookie, as demonstrated by changing 4gH40df5language=en to 4gH40df5language=en'.phpinfo().'; (if the random prefix 4gH40df5 were used).