** DISPUTED ** BigTree CMS through 4.2.18 allows remote authenticated users to execute arbitrary code by uploading a crafted package containing a PHP web shell, related to extraction of a ZIP archive to filename patterns such as cache/package/xxx/yyy.php. This issue exists in core\admin\modules\developer\extensions\install\unpack.php and core\admin\modules\developer\packages\install\unpack.php. NOTE: the vendor states "You must implicitly trust any package or extension you install as they all have the ability to write PHP files."