The MainWP Child – Securely Connects to the MainWP Dashboard to Manage Multiple Sites plugin for WordPress is vulnerable to privilege escalation due to a missing authorization checks on the register_site function in all versions up to, and including, 5.2 when a site is left in an unconfigured state. This makes it possible for unauthenticated attackers to log in as an administrator on instances where MainWP Child is not yet connected to the MainWP Dashboard. IMPORTANT: this only affects sites who have MainWP Child installed and have not yet connected to the MainWP Dashboard, and do not have the unique security ID feature enabled. Sites already connected to the MainWP Dashboard plugin and do not have the unique security ID feature enabled, are NOT affected and not required to upgrade. Please note 5.2.1 contains a partial patch, though we consider 5.3 to be the complete patch.
The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
Assuming a user with a given identity, authorization is the process of determining whether that user can access a given resource, based on the user’s privileges and any permissions or other access-control specifications that apply to the resource. When access control checks are not applied, users are able to access data or perform actions that they should not be allowed to perform. This can lead to a wide range of problems, including information exposures, denial of service, and arbitrary code execution.