Craft CMS contains an authenticated remote code execution (RCE) vulnerability via the Twig sandbox escape mechanism. The vulnerability arises because the Twig sandbox's allowlisting permits dangerous functionality from the Yii framework, specifically through a function-call gadget in yii\base\Component. An authenticated user with control panel access can exploit this by rendering a malicious Twig template, bypassing sandbox protections. This affects Craft CMS versions from 4.0.0-RC1 up to but not including 4.18.3, and 5.0.0-RC1 up to but not including 5.10.7. A patch is available to remediate this issue.