Auth bypass in Themetechmount Truebooker – Appointment Booking And Scheduler System

CVE-2026-18315

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.

Vulnerability class: IDOR (Insecure Direct Object Reference)

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-18315?
CVE-2026-18315 is a critical-severity vulnerability in Themetechmount Truebooker – Appointment Booking And Scheduler System, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 9.8/10. Published 2026-08-19.
How severe is CVE-2026-18315?
Critical severity. CVSS v3 base score is 9.8 out of 10.