Unrestricted File Upload exists in BigTree CMS through 4.2.18: if an attacker uploads an 'xxx.pht' or 'xxx.phtml' file, they could bypass a safety check and execute any code.
CSRF exists in BigTree CMS through 4.2.18 with the force parameter to /admin/pages/revisions.php - for example: /admin/pages/revisions/1/?force=false. A page with id=1 can be unlocked.
BigTree CMS through 4.2.17 relies on a substring check for CSRF protection, which allows remote attackers to bypass this check by placing the required admin/developer/ URI within a query string in an HTTP Referer header. This was found in core/admin/modules/developer/_header.php and patched in core/inc/bigtree/admin.php on 2017-04-14.