CVE-2026-4807 json
Appointment Booking Calendar <= 1.6.10.6 - Unauthenticated Arbitrary Appointment View, Modification and Deletion
published 2026-05-07 6 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-28236
- cvss
- 6.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 42%
- public exploits
- 0
- none known
Summary
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.
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 6 mo ago
Exploit prediction
0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L |
Affected products
- croixhaug Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin
Classification
- Weakness
-
- CWE-862 Missing Authorization
- Technology feeds
References
- wordfence.com /threat-intel/vulnerabilities/id/436ab843-7729-4d57-9c9e-2ede2f101ddb?source=cve
- plugins.trac.wordpress.org /browser/simply-schedule-appointments/tags/1.6.9.29/includes/lib/td-util/class-td-api-model.php#L361
- plugins.trac.wordpress.org /browser/simply-schedule-appointments/tags/1.6.9.29/includes/lib/td-util/class-td-api-model.php#L110
- plugins.trac.wordpress.org /browser/simply-schedule-appointments/tags/1.6.9.29/includes/class-appointment-model.php#L698
- plugins.trac.wordpress.org /browser/simply-schedule-appointments/tags/1.6.9.29/includes/class-shortcodes.php#L889
- plugins.trac.wordpress.org /browser/simply-schedule-appointments/tags/1.6.9.29/booking-app-new/iframe-inner.php#L444
- plugins.trac.wordpress.org /browser/simply-schedule-appointments/tags/1.6.9.29/includes/class-bootstrap.php#L151
- plugins.trac.wordpress.org /changeset/3511993/simply-schedule-appointments/trunk/includes
Sources
- CVE List CVE-2026-4807
- NVD CVE-2026-4807
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.