CVE-2025-15488: Responsive Plus WordPress Plugin RCE Flaw

CVE-2025-15488 Overview

CVE-2025-15488 is an arbitrary shortcode execution vulnerability affecting the Responsive Plus WordPress plugin before version 3.4.3. The vulnerability exists because the plugin allows unauthenticated users to execute the update_responsive_woo_free_shipping_left_shortcode AJAX action, which fails to properly validate the content_rech_data parameter before processing it as a shortcode. This improper input validation enables attackers to execute arbitrary WordPress shortcodes without authentication.

Critical Impact

Unauthenticated attackers can exploit this vulnerability to execute arbitrary shortcodes on vulnerable WordPress installations, potentially leading to information disclosure, unauthorized actions, or further exploitation depending on available shortcodes.

Affected Products

• Responsive Plus WordPress plugin versions prior to 3.4.3

Discovery Timeline

• 2026-03-26 - CVE CVE-2025-15488 published to NVD
• 2026-03-26 - Last updated in NVD database

Technical Details for CVE-2025-15488

Vulnerability Analysis

This vulnerability is classified as an Improper Input Validation issue that enables arbitrary shortcode execution. The Responsive Plus WordPress plugin exposes an AJAX action called update_responsive_woo_free_shipping_left_shortcode that can be accessed by unauthenticated users. The core security flaw lies in the plugin's failure to properly sanitize and validate the content_rech_data parameter before passing it to WordPress's shortcode processing functionality.

WordPress shortcodes are powerful features that allow plugins and themes to execute specific functionality through simple text tags. When an application processes user-controlled input as shortcodes without proper validation, attackers can invoke any registered shortcode on the system. This can lead to various security impacts depending on what shortcodes are available, including data exfiltration, privilege escalation, or execution of other plugin functionality that should require authentication.

Root Cause

The root cause of this vulnerability is insufficient input validation in the AJAX handler for the update_responsive_woo_free_shipping_left_shortcode action. The plugin processes the content_rech_data parameter as a WordPress shortcode without first verifying that the request comes from an authenticated user with appropriate permissions, and without sanitizing the input to prevent arbitrary shortcode execution. The AJAX endpoint lacks proper nonce verification and capability checks that are standard security practices for WordPress plugin development.

Attack Vector

The attack can be executed remotely over the network without requiring any authentication. An attacker would craft a malicious HTTP request to the WordPress AJAX endpoint (/wp-admin/admin-ajax.php) with the action parameter set to update_responsive_woo_free_shipping_left_shortcode and the content_rech_data parameter containing arbitrary shortcode syntax. When the vulnerable plugin processes this request, it will execute whatever shortcode is provided, potentially exposing sensitive information or triggering unintended functionality.

The attack requires no user interaction and can be automated against multiple WordPress installations. Attackers may enumerate available shortcodes on the target system to identify those that could be abused for maximum impact, such as shortcodes that display user data, modify database entries, or interact with other plugins.

Detection Methods for CVE-2025-15488

Indicators of Compromise

• Unusual POST requests to /wp-admin/admin-ajax.php with action parameter update_responsive_woo_free_shipping_left_shortcode from unauthenticated sessions
• Presence of shortcode syntax (bracket notation like [shortcode_name]) in content_rech_data parameter values in access logs
• Unexpected shortcode execution logs or errors in WordPress debug logs
• Anomalous data access patterns that may indicate shortcode-based information disclosure

Detection Strategies

• Implement Web Application Firewall (WAF) rules to monitor and alert on requests to the vulnerable AJAX endpoint containing shortcode patterns
• Enable WordPress debug logging and monitor for unexpected shortcode execution attempts
• Review Apache/Nginx access logs for POST requests to admin-ajax.php with the vulnerable action parameter
• Deploy intrusion detection systems configured to identify WordPress-specific attack patterns

Monitoring Recommendations

• Configure real-time alerting for any unauthenticated requests to the vulnerable AJAX action
• Establish baseline metrics for legitimate AJAX traffic and alert on anomalies
• Monitor server resource usage as shortcode abuse may cause unusual processing loads
• Implement log aggregation to correlate attack attempts across multiple WordPress installations

How to Mitigate CVE-2025-15488

Immediate Actions Required

• Update the Responsive Plus WordPress plugin to version 3.4.3 or later immediately
• If immediate update is not possible, temporarily deactivate the Responsive Plus plugin until patching can be completed
• Review access logs for evidence of exploitation attempts targeting the vulnerable endpoint
• Conduct a security audit of shortcode functionality and registered shortcodes on the WordPress installation

Patch Information

The vulnerability has been addressed in Responsive Plus WordPress plugin version 3.4.3. Site administrators should update through the WordPress plugin management interface or by downloading the latest version directly. For detailed vulnerability information and remediation guidance, refer to the WPScan Vulnerability Report.

Workarounds

• Temporarily disable the Responsive Plus plugin if updating is not immediately feasible
• Implement a WAF rule to block requests containing the update_responsive_woo_free_shipping_left_shortcode action parameter
• Restrict access to admin-ajax.php at the web server level for unauthenticated users if it does not break other site functionality
• Consider implementing IP-based access controls to limit exposure while awaiting patch deployment

# Apache .htaccess rule to block the vulnerable AJAX action
# Add to WordPress root .htaccess file
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_URI} ^/wp-admin/admin-ajax\.php
RewriteCond %{QUERY_STRING} action=update_responsive_woo_free_shipping_left_shortcode [OR]
RewriteCond %{REQUEST_BODY} action=update_responsive_woo_free_shipping_left_shortcode
RewriteRule .* - [F,L]
</IfModule>