CVE-2026-86475

Appointment Hour Booking <= 1.5.94 - Unauthenticated Appointment Slot Capacity Bypass

2026-09-14 00:00

Strategic Overview

Status: Patched in 1.5.95
Affected Plugin: Appointment Hour Booking – Booking Calendar
Affected Version: <= 1.5.94
CVSS: 5.3Medium
Weakness type: CWE-602 · Client-Side Enforcement of Server-Side Security
CVE: CVE-2026-86475

View all Appointment Hour Booking – Booking Calendar vulnerabilities

At a glance

CVE-2026-86475 is a medium-severity Client-Side Enforcement of Server-Side Security vulnerability in the Appointment Hour Booking WordPress plugin, affecting versions <= 1.5.94. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 1.5.95; sites on affected versions should update now. Disclosed September 2026, reported by Nicat Sultanov.

Vulnerability Overview

The Appointment Hour Booking plugin for WordPress is vulnerable to Payment Bypass in all versions up to, and including, 1.5.94. This is due to the double-booking verification only checking the first appointment in a multi-appointment submission (`apps[0]`) rather than iterating over all submitted appointments. This makes it possible for unauthenticated attackers to book appointments beyond the configured slot capacity by submitting multiple appointments in a single booking request, bypassing slot availability restrictions entirely.

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.

CWE-602: Client-Side Enforcement of Server-Side Security

The product is composed of a server that relies on the client to implement a mechanism that is intended to protect the server.

Remediation

Update to version 1.5.95, 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: Appointment Hour Booking 1.5.95 closes this, and updating the plugin is the step that ends it.

Login Security
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-86475 https://www.wordfence.com/threat-intel/vulnerabilities/id/b6d9539f-1f75-49ca-b7b8-a400e948d6b5 https://nvd.nist.gov/vuln/detail/CVE-2026-86475

Related records

Same weakness class

5.3CVE-2026-16282: Appointment Hour Booking <= 1.5.87 Price ManipulationCVE-2026-16282

Other vulnerabilities in Appointment Hour Booking – Booking Calendar

CVSS Vector

5.3

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityLow
AvailabilityNone

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