CVE-2026-11887: Salon Booking System Auth Bypass Flaw

CVE-2026-11887 Overview

CVE-2026-11887 affects the Salon Booking System WordPress plugin in versions before 10.30.20. The plugin fails to enforce proper authorization checks on one of its AJAX actions. Any authenticated user, including a low-privileged subscriber, can modify plugin settings and bypass the manual approval requirement for new bookings. This flaw represents a broken access control weakness that undermines the plugin's booking workflow integrity. Salon operators relying on manual approval to vet appointments lose that control when the vulnerability is exploited.

Critical Impact
Authenticated users with minimal privileges can alter plugin configuration and bypass the manual booking approval workflow, compromising business logic integrity.

Affected Products

Salon Booking System WordPress plugin versions prior to 10.30.20

Discovery Timeline

2026-07-01 - CVE-2026-11887 published to NVD
2026-07-01 - Last updated in NVD database

Technical Details for CVE-2026-11887

Vulnerability Analysis

The Salon Booking System plugin exposes an AJAX action that lacks proper authorization enforcement. The handler verifies that the request comes from an authenticated user but does not validate whether that user holds the required role or capability to modify plugin settings. This classification aligns with Broken Access Control and Missing Authorization weaknesses.

WordPress subscribers are the lowest-privileged authenticated role and are commonly created through open registration on booking-oriented sites. Because the AJAX endpoint accepts requests from any logged-in user, a subscriber can invoke it to change the setting that governs the manual approval of new bookings. Once that setting is disabled, bookings are auto-approved without operator review.

Root Cause

The root cause is the absence of a capability check, such as current_user_can('manage_options'), inside the AJAX handler registered via wp_ajax_ hooks. Authentication alone is treated as sufficient authorization. The plugin also does not segregate administrative AJAX endpoints from those intended for end-user booking actions.

Attack Vector

An attacker registers or uses an existing subscriber-level account on a vulnerable WordPress site. The attacker then sends a crafted POST request to the WordPress AJAX endpoint targeting the vulnerable action with parameters that toggle the manual approval setting. Because the request originates from an authenticated session, WordPress passes it to the plugin handler, which processes the change without verifying the user's role.

For technical details, refer to the WPScan Vulnerability Report.

Detection Methods for CVE-2026-11887

Indicators of Compromise

Unexpected changes to Salon Booking System plugin settings, particularly toggles related to manual booking approval
Bookings appearing as auto-approved despite site policy requiring manual review
POST requests to /wp-admin/admin-ajax.php originating from subscriber-level accounts targeting Salon Booking System actions

Detection Strategies

Review WordPress audit logs for setting modifications performed by non-administrator accounts
Correlate subscriber account activity with AJAX requests to the plugin's action handlers
Alert on newly registered subscriber accounts that immediately issue admin-ajax requests

Monitoring Recommendations

Enable a WordPress activity logging plugin to record setting changes with user attribution
Forward web server access logs to a centralized log platform and query for admin-ajax.php requests filtered by referrer and user role
Monitor booking volume and approval status trends for anomalies that suggest bypassed manual review

How to Mitigate CVE-2026-11887

Immediate Actions Required

Update the Salon Booking System WordPress plugin to version 10.30.20 or later
Audit current plugin settings and restore the manual approval configuration if it was tampered with
Review subscriber accounts for suspicious registrations and remove accounts that are not required

Patch Information

The vendor has released version 10.30.20 of the Salon Booking System plugin, which introduces the missing authorization check on the affected AJAX action. Site administrators should apply this update through the WordPress plugin manager or via WP-CLI.

Workarounds

Disable open user registration in WordPress General Settings if it is not required for site operation
Restrict access to /wp-admin/admin-ajax.php from untrusted sources using a web application firewall rule that filters on the vulnerable action name
Temporarily deactivate the Salon Booking System plugin until the patched version can be deployed

bash

# Configuration example: update the plugin using WP-CLI
wp plugin update salon-booking-system --version=10.30.20

# Verify the installed version
wp plugin get salon-booking-system --field=version

# Optionally disable open registration
wp option update users_can_register 0