CVE-2020-26212

GLPI stands for Gestionnaire Libre de Parc Informatique and it is a Free
Asset and IT Management Software package, that provides ITIL Service Desk
features, licenses tracking and software auditing. In GLPI before version
9.5.3, any authenticated user has read-only permissions to the planning of
every other user, even admin ones. Steps to reproduce the behavior: 1.
Create a new planning with ‘eduardo.mozart’ user (from ‘IT’ group that
belongs to ‘Super-admin’) into it’s personal planning at ‘Assistance’ >
‘Planning’. 2. Copy the CalDAV url and use a CalDAV client (e.g.
Thunderbird) to sync the planning with the provided URL. 3. Inform the
username and password from any valid user (e.g. ‘camila’ from ‘Proativa’
group). 4. ‘Camila’ has read-only access to ‘eduardo.mozart’ personal
planning. The same behavior happens to any group. E.g. ‘Camila’ has access
to ‘IT’ group planning, even if she doesn’t belong to this group and has a
‘Self-service’ profile permission). This issue is fixed in version 9.5.3.
As a workaround, one can remove the caldav.php file to block access to
CalDAV server.