PT-2026-38327 · Croixhaug · The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin
Athiwat Tiprasaharn
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Published
2026-05-07
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Updated
2026-05-07
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CVE-2026-4807
CVSS v3.1
6.5
Medium
| Vector | AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L |
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.
Fix
Missing Authorization
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Weakness Enumeration
Related Identifiers
Affected Products
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin