CVE-2026-2520

Online Scheduling and Appointment Booking System – Bookly <= 27.2 - Missing Authorization to Authenticated (Subscriber+) Limited Arbitrary Plugin Update

2026-09-07 00:00
KoreaInfoSec

Strategic Overview

Status
Patched in 27.3
Affected Plugin
Online Scheduling and Appointment Booking System – Bookly
Affected Version
<= 27.2
CVSS
5.4Medium
Weakness type
CWE-862 · Missing Authorization
CVE
CVE-2026-2520
View all Online Scheduling and Appointment Booking System – Bookly vulnerabilities

At a glance

CVE-2026-2520 is a medium-severity Missing Authorization vulnerability in the Online Scheduling and Appointment Booking System WordPress plugin, affecting versions <= 27.2. It carries a CVSS score of 5.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Subscriber level or above. The issue is fixed in version 27.3; sites on affected versions should update now. Disclosed September 2026, reported by KoreaInfoSec.

Vulnerability Overview

The Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the 'updateAddon' function in all versions up to, and including, 27.2. This makes it possible for authenticated attackers, with Subscriber-level access and above, to update any plugin with a main file of 'main.php' to its latest version.

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.

CWE-862: Missing Authorization

Online Scheduling and Appointment Booking System <= 27.2 carries this weakness at updateAddon, and reaching it takes an account at Subscriber level or above. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.

Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For Online Scheduling and Appointment Booking System the fix is 27.3: builds <= 27.2 are affected, anything from 27.3 onward is not.

Remediation

Update to version 27.3, or a newer patched version

How does WordSec protect against this?

Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: Online Scheduling and Appointment Booking System 27.3 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-2520https://www.wordfence.com/threat-intel/vulnerabilities/id/b7edc69b-363d-49df-b82b-a9ad4fe9224ahttps://nvd.nist.gov/vuln/detail/CVE-2026-2520

Related records

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