This vulnerability allows an authenticated attacker who has been granted the settings__edit capability - such as an agent or a user with a custom role - to modify the default registration role to administrator. Consequently, any new user registered through the LatePoint plugin will be assigned full WordPress administrator privileges. This vulnerability is particularly relevant for organizations where delegated administrative permissions are common within the LatePoint platform, as it provides a clear path for lower-privileged users to achieve full site compromise.

Attack Chain

1. An attacker obtains or is assigned a WordPress user role containing the settings__edit capability for the LatePoint plugin.
2. The attacker authenticates to the WordPress administration panel or interacts directly with the plugin's settings update API.
3. The attacker crafts a request to the OsSettingsController::update() handler.
4. The attacker injects the default_wp_role_for_customer parameter with the value administrator into the settings array of the update request.
5. The server-side code fails to validate the input against an allowlist, accepting the malicious value.
6. The OsSettingsHelper::prepare_value() method persists the new, unauthorized default role configuration to the database.
7. A new customer registers for an account via the LatePoint public-facing booking flow.
8. WordPress creates the new customer account using the attacker-modified default role, granting the new account administrative access.

Impact

Successful exploitation allows for the creation of unauthorized WordPress administrator accounts, leading to full site takeover, data exfiltration, and potential remote code execution on the underlying server. This affects any WordPress site running LatePoint version 5.7.3 or earlier that utilizes delegated role management for plugin settings.

Recommendation

1. Update the LatePoint Appointment Booking plugin to a version released after 5.7.3 that incorporates server-side role validation.
2. Audit all existing WordPress user roles and ensure that the settings__edit capability is restricted to trusted, verified administrators only.
3. Implement WAF rules to monitor for unusual POST requests to WordPress endpoints associated with the LatePoint settings controller that contain parameters referencing default_wp_role_for_customer.
4. Regularly review the wp_users and wp_usermeta tables for any newly created accounts with the administrator role to identify potential abuse.