Appointment Booking Plugin <= 5.7.4 — Unauthenticated Authentication Bypass via Race Condition on OTP Attempts Counter

Am I affected?

• Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Appointment Booking Plugin – LatePoint | Calendar & Scheduling for WordPress.
• No admin access? Run a passive check of your site. It reads public files only.
• No account is needed to exploit this. Treat any exposed site on an affected version as at risk.

What to do

1. Update to version 5.7.5, or a newer patched version
2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
3. Watch Appointment Booking Plugin – LatePoint | Calendar & Scheduling for WordPress to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to Ekene Umegakwe.

The Appointment Booking Plugin – LatePoint | Calendar & Scheduling for WordPress plugin for WordPress is vulnerable to Authentication Bypass via Race Condition in all versions up to, and including, 5.7.4. This is due to a non-atomic read-modify-write on the OTP verification attempts counter in the `verifyOTP` function: the counter is incremented using a stale in-memory value with no conditional `WHERE attempts < 10` guard on the `UPDATE` and no `SELECT ... FOR UPDATE` row lock, creating a TOCTOU window that allows concurrent requests to bypass the 10-attempt lockout. This makes it possible for unauthenticated attackers — who know a target customer's registered email address or phone number — to fire concurrent requests to the `auth__verify_otp` endpoint, defeat the lockout cap, brute-force the 6-digit OTP code, and authenticate as the targeted LatePoint customer, gaining full access to their account, bookings, and personal data. The nonce check present on the endpoint (`otp_verify_otp_nonce`) does not mitigate this issue, as the nonce is publicly emitted by the unauthenticated `request_otp` and `resend_otp` endpoints and is trivially obtainable by any unauthenticated attacker prior to launching the race.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

• Advisorywordfence.com

Related CVEs

Timeline

1. Oct 16, 2026

   CVE published

   Severity critical, CVSS 9.1

2. Nov 13, 2026

   Record last updated