Online Scheduling and Appointment Booking System <= 28.2 - Unauthenticated Authorization Bypass via PHP Type Juggling via 'verification_code' Parameter Type Juggling via json_data
The Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to Authorization Bypass via PHP Type Juggling in all versions up to, and including, 28.2. This is due to the postValidateCustomer() function using a loose PHP inequality operator (!=) to compare the session-stored one-time verification code against the attacker-supplied verification_code parameter — a flaw that is further exposed by the booking AJAX controller registering all its methods as wp_ajax_nopriv_ handlers and unconditionally overriding csrfTokenValid() to return true, leaving the endpoint both unauthenticated and CSRF-unprotected. This makes it possible for unauthenticated attackers to bypass the phone/email ownership verification step and overwrite the name, email, phone, and address fields of any arbitrary existing Bookly customer record, redirecting that customer's booking notifications to attacker-controlled contact details. The bypass is achievable because the json_data input channel decodes input via json_decode(), which preserves real PHP types and causes the wp_kses filter to leave non-string values such as the JSON boolean true untouched; submitting true as the verification_code satisfies the loose comparison against the session's non-zero integer code (generated by mt_rand(100000, 999999)), causing true != <non-zero int> to evaluate as false and the guard to be bypassed.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| WordPress plugin | Online Scheduling and Appointment Booking System – Bookly | <= 28.2 | 28.3 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N- Weakness (CWE)
CWE-285- Platform
- WordPress
- Package
Online Scheduling and Appointment Booking System – Bookly- Disclosed
- 24.09.2026
- Updated
- 11.10.2026 10:23
Sources and licenses
Wordfence Intelligence - d24fa600-7698-4081-92f5-e11606928886 - Wordfence Intelligence
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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 <= 28.2 - Unauthenticated Authorization Bypass via PHP Type Juggling via 'verification_code' Parameter Type Juggling via json_data this entry
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