security/MemberLoginForm.php in SilverStripe 3.0.3 supports credentials in a GET request, which allows remote or local attackers to obtain sensitive information by reading web-server access logs, web-server Referer logs, or the browser history, a similar vulnerability to CVE-2013-2653.
https://github.com/chillu/silverstripe-framework/commit/3e88c98ca513880e2b43ed7f27ade17fef5d9170