What’s Vulnerable › Vulnerabilities
CVE-2026-6937: Appointment Booking Calendar <= 1.6.11.8 - Missing Authorization to Unauthenticated Arbitrary Modification via Bulk Appointments REST API Endpoint
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.6% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-05-28 · updated 2026-06-17
- Weakness: CWE-862
Description
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 1.6.11.8 due to the plugin not properly verifying that a user is authorized to perform an action via the bulk appointments REST API endpoint. This makes it possible for unauthenticated attackers to modify arbitrary appointment records including customer PII, payment status, and meeting URL fields, and to expose full customer PII from existing appointment records via the bulk endpoint response. The public nonce is a static, user-independent value present in the HTML source of any page hosting the [ssa_booking] shortcode, meaning any visitor who has viewed such a page can obtain it and target any appointment in the system without authentication.
Affected products
- croixhaug Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin: through 1.6.11.8
References
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.10.0/includes/class-appointment-model.php#L724
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.10.0/includes/class-bootstrap.php#L151
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.10.0/includes/lib/td-util/class-td-api-model.php#L74
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.11.0/includes/class-appointment-model.php#L724
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.11.0/includes/class-bootstrap.php#L151
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.11.0/includes/lib/td-util/class-td-api-model.php#L74
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/trunk/includes/class-appointment-model.php#L724
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/trunk/includes/class-bootstrap.php#L151
- https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/trunk/includes/lib/td-util/class-td-api-model.php#L74
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3549843%40simply-schedule-appointments&new=3549843%40simply-schedule-appointments&sfp_email=&sfph_mail=
- https://www.wordfence.com/threat-intel/vulnerabilities/id/ef0f5f9d-788a-4cf8-9747-ada076a69a1f?source=cve
Get alerted when CVE-2026-6937 or the next vulnerability affects your stack