CVE-2026-18315

TrueBooker <= 1.2.6 - Unauthenticated Authorization Bypass Through User-Controlled Key to Account Takeover to 'truebooker_wp_user_id' Parameter

2026-08-18 14:52
Décio Brandão

Strategic Overview

Status
Patched in 1.2.7
Affected Plugin
TrueBooker – Appointment Booking and Scheduler System
Affected Version
<= 1.2.6
CVSS
9.8Critical
Weakness type
CWE-639 · Authorization Bypass Through User-Controlled Key
CVE
CVE-2026-18315
View all TrueBooker – Appointment Booking and Scheduler System vulnerabilities

At a glance

CVE-2026-18315 is a critical-severity Authorization Bypass Through User-Controlled Key vulnerability in the TrueBooker WordPress plugin, affecting versions <= 1.2.6. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 1.2.7; sites on affected versions should update now. Disclosed August 2026, reported by Décio Brandão.

Vulnerability Overview

The TrueBooker – Appointment Booking and Scheduler System plugin for WordPress is vulnerable to Authorization Bypass Through User-Controlled Key leading to Account Takeover in all versions up to, and including, 1.2.6. This is due to the admin_user_create_cus AJAX handler lacking any authentication or capability check before passing the attacker-supplied truebooker_wp_user_id parameter directly to wp_update_user. This makes it possible for unauthenticated attackers to overwrite the email address of any WordPress user — including an administrator — and then complete the standard WordPress lost-password flow to fully take over the targeted account.

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 privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-639: Authorization Bypass Through User-Controlled Key

Reaching this weakness in TrueBooker <= 1.2.6 takes no account at all. Authorization bypass through a user-controlled key, often called insecure direct object reference, means the application looks up a record by an identifier from the request without checking that the caller owns it.

Changing a number in the request is enough to read or modify other users' records, which on commerce and membership sites means customer data. For TrueBooker the fix is 1.2.7: builds <= 1.2.6 are affected, anything from 1.2.7 onward is not.

Remediation

Update to version 1.2.7, or a newer patched version

How does WordSec protect against this?

This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: TrueBooker 1.2.7 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-18315https://www.wordfence.com/threat-intel/vulnerabilities/id/73251a74-5be3-446b-8e0a-ff2d1484c467https://nvd.nist.gov/vuln/detail/CVE-2026-18315

Related records

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