Authenticated RCE via render-components Entry Type overrides

Craft CMS 5.10.13.2 contains an authenticated remote code execution vulnerability in the Control Panel action app/render-components.

Any authenticated user with basic Control Panel access can submit request-controlled component classes and property overrides. By first overriding an EntryType object’s uiLabelFormat and then rendering an Entry that resolves the same request-cached entry type, an attacker can cause arbitrary Twig supplied in the request to be evaluated by renderObjectTemplate().

This render path is not sandboxed. A Twig string callable can therefore reach PHP functions such as system(), resulting in operating-system command execution with the privileges of the PHP/web-server process.

The issue was reproduced with an active non-admin Craft Team user with no optional permissions enabled. No access to entry-editing, Settings, utility, user-management, project-config, filesystem, Kubernetes, or environment variables was required.