Invision Community through 4.7.16 allows remote code execution via the applications/core/modules/admin/editor/toolbar.php IPS\core\modules\admin\editor\_toolbar::addPlugin() method. This method handles uploaded ZIP files that are extracted into the applications/core/interface/ckeditor/ckeditor/plugins/ directory without properly verifying their content. This can be exploited by admin users (with the toolbar_manage permission) to write arbitrary PHP files into that directory, leading to execution of arbitrary PHP code in the context of the web server user.
