Member_ProfileForm in security/Member.php in SilverStripe 2.3.x before 2.3.7 allows remote attackers to hijack user accounts by saving data using the email address (ID) of another user.
SilverStripe 2.3.x before 2.3.10 and 2.4.x before 2.4.4 allows remote attackers to bypass the cross-site request forgery (CSRF) protection mechanism and hijack the authentication of administrators via vectors related to "form action requests" using a controller.
In SilverStripe through 4.6.0-rc1, a FormField with square brackets in the field name skips validation.