In GLPI from version 9.1 and before version 9.4.6, any API user with READ right on User itemtype will have access to full list of users when querying apirest.php/User. The response contains: - All api_tokens which can be used to do privileges escalations or read/update/delete data normally non accessible to the current user. - All personal_tokens can display another users planning. Exploiting this vulnerability requires the api to be enabled, a technician account. It can be mitigated by adding an application token. This is fixed in version 9.4.6.