Описание
Craft CMS: RCE via missing cleanseConfig in FieldsController::actionRenderCardPreview
The actionRenderCardPreview() method in FieldsController passes the fieldLayoutConfig POST parameter directly to Fields::createLayout() without calling Component::cleanseConfig(). This allows Yii2 event handler injection via on eventName keys in the config array, leading to arbitrary code execution.
This is the same vulnerability pattern that was fixed in GHSA-4484-8v2f-5748 (same file, _fldComponent method correctly uses cleanseConfig), GHSA-qx2q-q59v-wf3j (EntryTypesController), and GHSA-2fph-6v5w-89hh (ElementIndexesController).
PoC
As an admin user with a valid session:
When the FieldLayout object is constructed, Yii2 processes the on init key as an event handler registration. During Component::init(), the init event is triggered, calling phpinfo(). The phpinfo output (which includes environment variables, potentially containing database credentials and CRAFT_SECURITY_KEY) will appear in the response.
Impact
An authenticated admin can achieve RCE through Yii2 event handler injection. While this requires admin access (same as GHSA-4484-8v2f-5748, which was rated moderate), it allows arbitrary PHP function execution and information disclosure via phpinfo.
Пакеты
craftcms/cms
>= 5.5.0, <= 5.9.13
5.9.14
Связанные уязвимости
Craft CMS (composer package craftcms/cms) versions >= 5.5.0 and <= 5.9.13 contain a remote code execution vulnerability in the FieldsController::actionRenderCardPreview() method, which passes the fieldLayoutConfig POST parameter directly to Fields::createLayout() without calling Component::cleanseConfig(). An authenticated admin user can inject Yii2 event handlers (e.g., 'on init' keys) via the fieldLayoutConfig parameter to execute arbitrary PHP code and disclose sensitive information (such as environment variables containing database credentials and CRAFT_SECURITY_KEY). The issue is fixed in version 5.9.14.