CVE-2026-4807Appointment Booking Calendar <= 1.6.10.6 - Unauthenticated Arbitrary Appointment View, Modification and Deletion
- 6.5MediumCVSS base score
- 0.49%Exploitation in 30 daysEPSS · top 57% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By Wordfence
- 43 days later
· 43 days later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| WordfenceCNA (assigner) | 3.1 | Medium6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L |
| NVDNVD · Deferred | 3.1 | Medium6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L |
- EPSS (exploitation in 30 days)
- 0.49% · top 57% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.
Affected products
croixhaug · Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin
- affected ≤ 1.6.10.6
References
References8
- https://www.wordfence.com/threat-intel/vulnerabilities/id/436ab843-7729-4d57-9c9e-2ede2f101ddb?source=cve (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.29/includes/lib/td-util/class-td-api-model.php#L361 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.29/includes/lib/td-util/class-td-api-model.php#L110 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.29/includes/class-appointment-model.php#L698 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.29/includes/class-shortcodes.php#L889 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.29/booking-app-new/iframe-inner.php#L444 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.29/includes/class-bootstrap.php#L151 (opens in a new tab)
- https://plugins.trac.wordpress.org/changeset/3511993/simply-schedule-appointments/trunk/includes (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-28236 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-4807)Record last updated .