SilverStripe 2.3.x before 2.3.10 and 2.4.x before 2.4.4 uses weak entropy when generating tokens for (1) the CSRF protection mechanism, (2) autologin, (3) "forgot password" functionality, and (4) password salts, which makes it easier for remote attackers to bypass intended access restrictions via unspecified vectors.
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.
In SilverStripe through 4.6.0-rc1, a FormField with square brackets in the field name skips validation.