CVE-2026-28104: Site Suggest Auth Bypass Vulnerability

CVE-2026-28104 Overview

CVE-2026-28104 is a Missing Authorization vulnerability discovered in the WordPress Site Suggest plugin developed by Aryan Shirani Bid Abadi. This broken access control flaw allows unauthenticated attackers to access functionality that is not properly constrained by Access Control Lists (ACLs), potentially leading to unauthorized data modification and service disruption.

Critical Impact

Unauthenticated attackers can bypass authorization controls to access restricted plugin functionality, potentially compromising site integrity and availability.

Affected Products

• Site Suggest plugin versions from n/a through 1.3.9
• WordPress installations using the vulnerable Site Suggest plugin

Discovery Timeline

• 2026-03-05 - CVE-2026-28104 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2026-28104

Vulnerability Analysis

This vulnerability stems from a Missing Authorization weakness (CWE-862) in the Site Suggest WordPress plugin. The plugin fails to implement proper authorization checks on certain functionality, allowing attackers to access features that should be restricted to authenticated users with appropriate permissions.

The flaw enables network-based attacks that require no authentication or user interaction. While the vulnerability does not allow direct data exfiltration (confidentiality is not impacted), successful exploitation can result in unauthorized modification of data and partial disruption of service availability.

Root Cause

The root cause is the absence of proper capability checks and nonce verification in the Site Suggest plugin's AJAX handlers or administrative functions. WordPress plugins must implement current_user_can() checks and verify nonces to ensure that only authorized users can execute sensitive operations. The Site Suggest plugin fails to properly constrain access to certain functionality, allowing any unauthenticated user to invoke these operations.

Attack Vector

The attack vector is network-based, requiring no privileges and no user interaction. An attacker can directly send crafted HTTP requests to the vulnerable WordPress installation to trigger the unprotected functionality. The attack has low complexity and can be executed remotely against any WordPress site running the vulnerable plugin version.

The exploitation typically involves:

1. Identifying WordPress installations with the Site Suggest plugin active
2. Crafting HTTP requests to access plugin endpoints that lack authorization checks
3. Executing privileged operations without proper authentication or capability verification

Detection Methods for CVE-2026-28104

Indicators of Compromise

• Unexpected HTTP requests to Site Suggest plugin endpoints from unauthenticated sources
• Unusual modifications to site suggestion data or plugin settings
• Abnormal patterns in WordPress admin-ajax.php requests targeting Site Suggest actions
• Log entries showing plugin functionality accessed without valid authentication cookies

Detection Strategies

• Monitor WordPress access logs for suspicious requests to /wp-admin/admin-ajax.php with Site Suggest action parameters
• Implement Web Application Firewall (WAF) rules to detect and block unauthorized access attempts to plugin endpoints
• Review WordPress audit logs for unexpected changes to plugin-managed data
• Deploy endpoint monitoring solutions to track plugin file access patterns

Monitoring Recommendations

• Enable comprehensive logging for WordPress AJAX requests and plugin activities
• Configure alerting for failed authorization attempts or anomalous plugin interactions
• Regularly audit Site Suggest plugin configurations and data for unauthorized modifications
• Implement real-time monitoring of WordPress admin actions and plugin API calls

How to Mitigate CVE-2026-28104

Immediate Actions Required

• Update the Site Suggest plugin to a patched version when available from the vendor
• Deactivate and remove the Site Suggest plugin if not essential to site operations
• Implement additional access controls at the web server or WAF level to restrict plugin endpoint access
• Review WordPress site for any unauthorized modifications that may have occurred

Patch Information

Refer to the Patchstack Vulnerability Report for the latest patch information and remediation guidance. WordPress administrators should monitor the plugin repository for updated versions that address this vulnerability.

Workarounds

• Disable the Site Suggest plugin until a security update is released
• Implement server-level access restrictions to block unauthenticated requests to plugin endpoints
• Use a security plugin with virtual patching capabilities to add authorization checks
• Configure .htaccess rules to restrict access to the plugin's AJAX handlers to authenticated users only

# Apache .htaccess workaround to restrict plugin access
# Add to WordPress root .htaccess file
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{REQUEST_URI} ^.*admin-ajax\.php.*$
    RewriteCond %{QUERY_STRING} action=site_suggest [NC]
    RewriteCond %{HTTP_COOKIE} !wordpress_logged_in
    RewriteRule .* - [F,L]
</IfModule>