GHSA-C4WF-2XXC-68QM Grav: FlexDirectory::dynamicDataField() executes arbitrary callables from blueprint data with no validation

Summary A missing validation check in Grav's Flex framework lets an account holding nothing but an ordinary object-create permission on a single Flex directory execute arbitrary shell commands on the server. Any authenticated user with create or update rights on a Flex-based directory Flex Users,...