CVE-2026-12626

Online Scheduling and Appointment Booking System <= 28.2 - Authenticated (Custom+) PHP Object Injection via 'value' Parameter

2026-10-09 17:51
Muni Nitish Kumar Yaddala (Stranger825)

Strategic Overview

Status
Patched in 28.3
Affected Plugin
Online Scheduling and Appointment Booking System – Bookly
Affected Version
<= 28.2
CVSS
7.2High
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE-2026-12626
View all Online Scheduling and Appointment Booking System – Bookly vulnerabilities

At a glance

CVE-2026-12626 is a high-severity Deserialization of Untrusted Data vulnerability in the Online Scheduling and Appointment Booking System WordPress plugin, affecting versions <= 28.2. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account at Custom level or above. The issue is fixed in version 28.3; sites on affected versions should update now. Disclosed October 2026, reported by Muni Nitish Kumar Yaddala (Stranger825).

Vulnerability Overview

The Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 28.2 via deserialization of untrusted input via the ‘value’ parameter. This makes it possible for authenticated attackers, with custom-level access and above, to inject a PHP Object. No known gadget chain is available.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-502: Deserialization of Untrusted Data

Online Scheduling and Appointment Booking System <= 28.2 carries this weakness at value, and reaching it takes an account at Custom level or above. Deserialization of untrusted data means the application reconstructs objects from input a caller controls, letting the attacker choose which classes get instantiated and what their properties hold.

A workable chain turns deserialization into file writes, deletions or code execution, depending on what the loaded classes do in their magic methods. For Online Scheduling and Appointment Booking System the fix is 28.3: builds <= 28.2 are affected, anything from 28.3 onward is not.

Remediation

Update to version 28.3, or a newer patched version

How does WordSec protect against this?

An attacker needs Custom access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: Online Scheduling and Appointment Booking System 28.3 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-12626https://www.wordfence.com/threat-intel/vulnerabilities/id/56c5e045-e91c-4517-8164-a21c3e99623bhttps://nvd.nist.gov/vuln/detail/CVE-2026-12626

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C