---
id: CVE-2026-13358
title: >-
  The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin
  plugin for WordPress is vulnerable to Insecure Direct Object Reference in all
  versions up to, and including, 1.6.12.10 via the ssa_past_appointments due to
  mi…
summary: >-
  The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin
  plugin for WordPress is vulnerable to Insecure Direct Object Reference in all
  versions up to, and including, 1.6.12.10 via the ssa_past_appointments due to
  mi…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-639
published: '2026-08-16'
updated: '2026-08-16'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-13358'
references:
  - url: >-
      https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.11.0/includes/class-appointment-model.php#L1936
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.11.0/includes/class-db-model.php#L325
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.11.0/includes/class-divi.php#L237
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.11.0/includes/class-divi.php#L254
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.11.0/includes/class-shortcodes.php#L781
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.12.4/includes/class-appointment-model.php#L1936
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.12.4/includes/class-db-model.php#L325
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.12.4/includes/class-divi.php#L237
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.12.4/includes/class-divi.php#L254
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.12.4/includes/class-shortcodes.php#L781
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/changeset?reponame=&old=3617759%40simply-schedule-appointments&new=3617759%40simply-schedule-appointments
    label: security@wordfence.com
  - url: >-
      https://www.wordfence.com/threat-intel/vulnerabilities/id/5dbe5094-d255-46b1-9e8e-9c48cd74e8a2?source=cve
    label: security@wordfence.com
tags:
  - nvd
ingestedAt: '2026-08-16T13:39:06.249Z'
epss: 0.00682
epssPercentile: 0.50367
---

## Overview

The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 1.6.12.10 via the ssa_past_appointments due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with contributor-level access and above, to access appointment records belonging to arbitrary users and harvest the per-appointment ownership tokens (32-character hashes) embedded in the rendered HTML, which can then be used without any authentication to read or modify those appointments including full customer PII such as name, email, phone number, and private notes. The /wp-json/ssa/v1/render-shortcode REST endpoint is registered unconditionally on rest_api_init regardless of whether the Divi theme is installed, and its permission callback only requires current_user_can('edit_posts'), meaning any Contributor-level account is sufficient to trigger this entire exploit chain.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.