CVE-2026-110653: Appointment Booking Plugin authentication bypass vulnerability
critical 9.1 published 2026-10-17 · updated 2026-10-19
- Affected versions
- 5.7.4 and older
- Fixed in
- 5.7.5 *
- Latest version
- 5.7.8
- Severity
- Critical · CVSS 9.1
- Active installs
- 100,000+
- Type
- Authentication bypass
* The source does not name a fixed version; this is the first wordpress.org release after the last affected version.
What an attacker needs
- Access: None. No account or login is needed.
CVSS vector (score by Wordfence): CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
What to do now
- Update Appointment Booking Plugin to 5.7.5 or newer (the latest is 5.7.8): Dashboard → Updates, or Plugins → “update now”.
- If you cannot update right away, deactivate it until you can.
- Turn on auto-updates for it: Plugins → “Enable auto-updates” on its row.
- Not sure which version you run? Check your version against every known Appointment Booking Plugin issue.
With WP-CLI:
wp plugin get latepoint --field=version. - If you ran an affected version and something looks off (new admin users, spam pages, redirects), run the free scan below.
The advisory
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.
References
- NVD CVE-2026-110653 nvd.nist.gov
- Wordfence advisory www.wordfence.com
- Plugin source plugins.trac.wordpress.org
Related
Ran an affected version? Check your site for signs of a hack
The free scan reads the public side of your site and looks for spam pages, hidden redirects, injected scripts and blacklist entries. No login, no install, about a minute.
Where this data comes from
- CVE record, score and references: NIST National Vulnerability Database (NVD), checked 2026-11-04. This product uses data from the NVD API but is not endorsed or certified by the NVD.
- Versions and install counts: wordpress.org/plugins/latepoint (Plugins API), fetched 2026-11-04.
- The summary, “what an attacker needs” and “what to do” sections are our plain-English reading of the record and the plugin's release history; the quoted description is the record's own text. Spot an error? Email Daniel.