Online Scheduling and Appointment Booking System <= 28.2 - Insecure Direct Object Reference to Unauthenticated Arbitrary Booking Token Disclosure and Deletion via 'order_id' Parameter

9.1
Authorization Bypass Through User-Controlled Key
CVE CVE-2026-93399
CVSS 9.1 (Critical)
Publicly Published September 24, 2026
Last Updated September 25, 2026
Researcher Theklis - Sentrium Security Ltd

Description

The Bookly plugin for WordPress is vulnerable to Insecure Direct Object Reference in versions up to, and including, 28.2 via the 'bookly_get_form_id', 'bookly_render_complete', 'bookly_add_to_calendar' and 'bookly_rollback_order' AJAX actions. This is due to the 'bookly_get_form_id' handler blindly storing the attacker-controlled 'order_id' from the submitted form_data into a new booking session, which the 'bookly_render_complete' handler then trusts to look up and return the corresponding Order's secret token without verifying that the current session created that order. This makes it possible for unauthenticated attackers to enumerate sequential order IDs, disclose other customers' order tokens, retrieve calendar/appointment information via 'bookly_add_to_calendar' and permanently delete arbitrary non-completed bookings via 'bookly_rollback_order', which cascade-deletes the customer_appointment and (when no other customers are attached) the underlying appointment.

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Vulnerability Details for Online Scheduling and Appointment Booking System – Bookly

Software Type Plugin
Software Slug bookly-responsive-appointment-booking-tool (view on wordpress.org)
Patched? Yes
Remediation Update to version 28.3, or a newer patched version
Affected Version
  • <= 28.2
Patched Version
  • 28.3

Recent vulnerabilities in Online Scheduling and Appointment Booking System – Bookly

# Title CVE ID CVSS Researchers Date
1 Bookly <= 28.2 - Unauthenticated Payment Bypass CVE-2026-86838 5.3 vuxvinh September 25, 2026
2 Bookly 23.2 - 28.2 - Authenticated (Bookly Administrator+) PHP Object Injection CVE-2026-86841 7.5 Muni Nitish Kumar Yaddala September 25, 2026
3 Bookly <= 28.2 - Authenticated (Staff+) Insecure Direct Object Reference CVE-2026-86839 4.3 Vũ Quang Huy September 25, 2026
4 Bookly <= 28.2 - Unauthenticated Insecure Direct Object Reference CVE-2026-86837 5.3 Artus KG September 25, 2026
5 Online Scheduling and Appointment Booking System <= 28.2 - Unauthenticated Authorization Bypass via PHP Type Juggling via 'verification_code' Parameter Type Juggling via json_data CVE-2026-92799 5.3 crow September 24, 2026
6 Online Scheduling and Appointment Booking System – Bookly <= 28.2 - Missing Authorization CVE-2026-96348 5.3 Ananda Dhakal September 24, 2026
7 Online Scheduling and Appointment Booking System – Bookly <= 28.2 - Authenticated (Subscriber+) Insecure Direct Object Reference CVE-2026-96347 4.3 Ananda Dhakal September 24, 2026
8 Bookly <= 28.1 - Unauthenticated Insecure Direct Object Reference CVE-2026-91847 5.3 vuxvinh September 17, 2026
9 Online Scheduling and Appointment Booking System <= 28.1 - Insecure Direct Object Reference to Unauthenticated Sensitive Data Access and Message Injection via 'conversation_id' Parameter CVE-2026-89063 7.5 jtb75 September 15, 2026
10 Online Scheduling and Appointment Booking System – Bookly <= 27.2 - Missing Authorization to Authenticated (Subscriber+) Limited Arbitrary Plugin Update CVE-2026-2520 5.4 KoreaInfoSec September 7, 2026

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