The Flex Objects plugin (through 1.4.6, tested with Grav 2.0.11) contains an incorrect authorization vulnerability in its Flex Objects API. FlexApiController::update() checks only the general Flex directory permission and does not apply the additional target/field/super-admin checks enforced by the dedicated Users and Groups API controllers. An authenticated account with api.access, admin.login, and users.update permissions (but without api.users.write or admin.super) can use the generic /api/v1/flex-objects/user-accounts endpoint to change a super administrator's password, or the /api/v1/flex-objects/user-groups endpoint to grant its group admin.super, resulting in full site takeover. Fixed in Flex Objects 1.4.7.

Grav Flex Objects plugin 1.4.0 before 1.4.17 contains an authorization bypass because its generic /api/v1/flex-objects/pages API routes check only directory-level admin.pages permissions, without enforcing the Pages API's api.pages.read/write permissions or page-level permissions rules. Authenticated non-super users with api.access and admin.pages or admin.configuration.pages permissions can read page source and frontmatter, modify content, or delete pages they are denied.