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Vulnerabilities

Vulnerability · CVE-2026-4807

The Appointment Booking Calendar plugin for WordPress is vulnerable to Missing Authorization in versions up to and including 1.6.10.6.

Published May 7, 2026 · catalog updated Jun 17, 2026 · The Appointment Booking Calendar

Check if you run it

No confirmed exploitation is on record for CVE-2026-4807. EPSS is 0.48%. Act only if a listed version of The Appointment Booking Calendar is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (The Appointment Booking Calendar).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.48%
Remediation
Version ranges on file
Affected products
stated named in the record

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • stated named in the record<= 1.6.10

How to fix CVE-2026-4807

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-4807. EPSS is 0.48%. Act only if a listed version of The Appointment Booking Calendar is installed.

Which versions are affected?

Compare what you have installed with named in the record <= 1.6.10. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-862: Missing Authorization. EPSS 0.48%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

WordPress security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. May 7, 2026 · NIST NVD

    Detected

    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 una

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 una

Sources

  • CVE.orgVulnerability recordCVE-2026-4807

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-4807

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-2026-4807

    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 non

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.