CVE-2026-25327: Restaurant Reservations Auth Bypass Flaw

CVE-2026-25327 Overview

CVE-2026-25327 is a Missing Authorization vulnerability affecting the Five Star Restaurant Reservations WordPress plugin developed by Rustaurius. This broken access control flaw allows unauthenticated attackers to exploit incorrectly configured access control security levels, potentially leading to unauthorized data modification and service disruption. The vulnerability affects all versions of the plugin through 2.7.9.

Critical Impact

Unauthenticated attackers can bypass access control mechanisms to perform unauthorized actions on restaurant reservation data, potentially disrupting business operations and compromising data integrity.

Affected Products

• Five Star Restaurant Reservations WordPress Plugin versions <= 2.7.9
• WordPress installations using the restaurant-reservations plugin
• Rustaurius Five Star Restaurant Reservations (all versions through 2.7.9)

Discovery Timeline

• 2026-03-25 - CVE-2026-25327 published to NVD
• 2026-03-26 - Last updated in NVD database

Technical Details for CVE-2026-25327

Vulnerability Analysis

This vulnerability is classified as CWE-862 (Missing Authorization), which occurs when the plugin fails to perform proper authorization checks before allowing access to restricted functionality. The Five Star Restaurant Reservations plugin contains endpoints or functions that do not adequately verify whether the requesting user has appropriate permissions to perform certain actions.

In WordPress plugin architecture, authorization checks typically rely on capability checks using functions like current_user_can(). When these checks are missing or improperly implemented, unauthorized users can access administrative functions or modify data they should not have access to. This vulnerability enables attackers to exploit the misconfigured access control, potentially allowing them to manipulate reservation data, view sensitive customer information, or disrupt the reservation system entirely.

Root Cause

The root cause of this vulnerability is the absence of proper authorization validation in the plugin's request handling logic. The plugin fails to verify user capabilities before processing sensitive operations, allowing requests from unauthenticated or low-privileged users to execute functions that should be restricted to administrators or authorized personnel only.

Attack Vector

The vulnerability is exploitable over the network without requiring authentication or user interaction. An attacker can send crafted HTTP requests directly to vulnerable endpoints exposed by the plugin. Since no authentication is required, the attack surface is significant for any WordPress site running the affected plugin versions.

The attack flow typically involves:

1. Identifying WordPress installations with the vulnerable plugin version
2. Crafting requests to target unprotected plugin endpoints
3. Exploiting the missing authorization checks to perform unauthorized actions
4. Manipulating reservation data or disrupting service availability

For detailed technical information, refer to the Patchstack Vulnerability Report.

Detection Methods for CVE-2026-25327

Indicators of Compromise

• Unexpected modifications to restaurant reservation entries without corresponding admin activity
• Unusual HTTP requests targeting plugin-specific AJAX handlers or REST API endpoints
• Access logs showing repeated requests to restaurant-reservations plugin endpoints from unknown IP addresses
• Database modifications to reservation tables without matching administrative sessions

Detection Strategies

• Monitor WordPress access logs for requests to /wp-admin/admin-ajax.php with restaurant-reservations related action parameters from unauthenticated sessions
• Implement Web Application Firewall (WAF) rules to detect and block suspicious requests targeting the plugin's endpoints
• Review WordPress audit logs for unauthorized changes to reservation data or plugin settings
• Deploy runtime application protection to monitor and alert on broken access control attempts

Monitoring Recommendations

• Enable detailed logging for WordPress AJAX and REST API requests
• Configure alerts for bulk modifications to reservation database tables
• Monitor for access patterns consistent with automated scanning or exploitation attempts
• Regularly audit user activity logs for anomalous reservation management actions

How to Mitigate CVE-2026-25327

Immediate Actions Required

• Update the Five Star Restaurant Reservations plugin to a patched version when available from the vendor
• Temporarily deactivate the plugin if reservation functionality is not critical until a patch is released
• Implement additional access controls at the web server or WAF level to restrict access to plugin endpoints
• Review and backup current reservation data to detect any unauthorized modifications

Patch Information

Check with Rustaurius, the plugin developer, for updated versions beyond 2.7.9 that address this authorization vulnerability. Monitor the Patchstack Vulnerability Report for patch availability and remediation guidance.

Workarounds

• Implement IP-based access restrictions for WordPress admin and AJAX endpoints at the web server level
• Deploy a Web Application Firewall with rules to enforce authentication requirements on plugin endpoints
• Limit network exposure of the WordPress installation using VPN or IP whitelisting for administrative access
• Consider using a security plugin that adds capability checks and monitors for authorization bypass attempts

# Example Apache .htaccess restriction for AJAX endpoints
<Files admin-ajax.php>
    Order Deny,Allow
    Deny from all
    # Allow from trusted IP addresses only
    Allow from 192.168.1.0/24
    Allow from 10.0.0.0/8
</Files>