Online Scheduling and Appointment Booking System <= 28.4 - Insecure Direct Object Reference to Authenticated (Subscriber+) Privilege Escalation via 'id' and 'wp_user_id' Parameters via Query String / JSON Body
The Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 28.4 via the 'id, wp_user_id' parameter due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with subscriber-level access and above, to overwrite the WordPress account binding of any Bookly staff record, including those owned by administrators, effectively hijacking a higher-privileged staff member's account association and escalating privileges. Exploitation requires the attacking user to be linked to at least one Bookly staff record, which occurs by default whenever an admin enables the bookly_gen_allow_staff_edit_profile option (active on fresh installs) and links a WordPress user to a staff entry.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| WordPress plugin | Online Scheduling and Appointment Booking System – Bookly | <= 28.4 | 28.5 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N- Weakness (CWE)
CWE-639- Platform
- WordPress
- Package
Online Scheduling and Appointment Booking System – Bookly- Disclosed
- 09.10.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
Wordfence Intelligence - 1c3cfaa5-00e3-41b6-8f38-cebdd5dec180 - Wordfence Intelligence
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Copyright 2012-2026 Defiant Inc.
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Vulnerability history: Online Scheduling and Appointment Booking System – Bookly
All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 32
- First → latest
- 02.2018 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 12
- Medium 19
Disclosures per year
- 2018: 1
- 2019: 0
- 2020: 0
- 2021: 1
- 2022: 0
- 2023: 5
- 2024: 1
- 2025: 0
- 2026: 24
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Online Scheduling and Appointment Booking System <= 28.4 - Insecure Direct Object Reference to Authenticated (Subscriber+) Privilege Escalation via 'id' and 'wp_user_id' Parameters via Query String / JSON Body this entry
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