CVE-2026-4807
Vulnérabilité moyenne dans Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin (croixhaug)
Description
The Appointment Booking Calendar plugin for WordPress is vulnerable to Missing Authorization in versions up to and including 1.6.10.6. This is due to a flawed authorization logic in the nonce_permissions_check() method combined with the public exposure of a site-wide reusable nonce. The plugin exposes a public_nonce value through the /wp-json/ssa/v1/embed-inner endpoint, which is accessible to unauthenticated users. The appointment deletion endpoint at /wp-json/ssa/v1/appointments/{id}/delete and /wp-json/ssa/v1/appointments/bulk use a permission check that accepts requests containing both an X-WP-Nonce header (with any arbitrary value) and an X-PUBLIC-Nonce header (with the valid public nonce). When the X-WP-Nonce validation fails, the function falls back to validating the X-PUBLIC-Nonce without properly rejecting the request. Since the public_nonce is exposed to all unauthenticated visitors and is site-wide (not user-specific or appointment-specific), attackers can obtain it and use it to view details of arbitrary appointments, including the public_edit_url, or delete arbitrary appointments by ID. This makes it possible for unauthenticated attackers to view, delete or modify any appointment in the system, disclosing sensitive appointment data, causing service disruption, and loss of booking records.
Gravité et risque d'exploitation
CVE-2026-4807 obtient un score CVSS de 6.5/10, soit une gravité moyenne. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.48 %, ce qui la place devant 39.9 % des CVE référencées.
Que faire ?
- Vérifiez si Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin (versions 0, <=1.6.10.6) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.
Références
- https://www.wordfence.com/threat-intel/vulnerabilities/id/436ab843-7729-4d57-9c9e-2ede2f101ddb?source=cve
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.29/includes/lib/td-util/class-td-api-model.php#L361
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.29/includes/lib/td-util/class-td-api-model.php#L110
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.29/includes/class-appointment-model.php#L698
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.29/includes/class-shortcodes.php#L889
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.29/booking-app-new/iframe-inner.php#L444
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.29/includes/class-bootstrap.php#L151
- https://plugins.trac.wordpress.org/changeset/3511993/simply-schedule-appointments/trunk/includes
