CVE-2025-13531: WordPress Stylish Order Form XSS Flaw

CVE-2025-13531 Overview

The Stylish Order Form Builder plugin for WordPress contains a Stored Cross-Site Scripting (XSS) vulnerability in the product_name parameter. This flaw exists in all versions up to and including version 1.0 due to insufficient input sanitization and output escaping. The vulnerability allows authenticated attackers with Subscriber-level access or higher to inject arbitrary web scripts into pages, which execute whenever a user accesses an affected page.

Critical Impact

Authenticated attackers can inject persistent malicious scripts that execute in the context of other users' sessions, potentially leading to session hijacking, credential theft, or unauthorized actions on behalf of administrators.

Affected Products

• Stylish Order Form Builder for WordPress versions up to and including 1.0

Discovery Timeline

• 2026-01-07 - CVE-2025-13531 published to NVD
• 2026-01-08 - Last updated in NVD database

Technical Details for CVE-2025-13531

Vulnerability Analysis

This Stored Cross-Site Scripting vulnerability arises from improper handling of user-supplied input in the product_name parameter within the Stylish Order Form Builder plugin. When users with Subscriber-level privileges or higher submit form data containing malicious JavaScript code through this parameter, the application fails to properly sanitize the input before storing it in the database and subsequently fails to escape the output when rendering the content.

The vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation), a common web application security weakness. The stored nature of this XSS variant makes it particularly dangerous because the malicious payload persists in the application's database and executes automatically whenever any user views the affected page.

Root Cause

The root cause of this vulnerability lies in insufficient input validation and output encoding within the plugin's form handling functionality. Specifically, the product_name parameter in the all-products.php file and associated functions in functions-admin.php do not implement proper sanitization routines. WordPress provides built-in functions such as sanitize_text_field() for input and esc_html() or esc_attr() for output, but these safeguards were not applied to the vulnerable parameter.

Attack Vector

The attack is conducted over the network and requires low-privilege authentication (Subscriber-level access). An attacker can exploit this vulnerability by:

1. Authenticating to the WordPress site with Subscriber-level or higher credentials
2. Navigating to form functionality provided by the Stylish Order Form Builder plugin
3. Injecting malicious JavaScript code into the product_name field
4. The payload is stored in the database without proper sanitization
5. When administrators or other users view the page containing the stored product data, the malicious script executes in their browser context

This allows attackers to potentially steal session cookies, perform actions on behalf of administrators, redirect users to malicious sites, or deface the WordPress installation. For detailed technical analysis, refer to the WordPress Plugin Code Review and WordPress Plugin Function Analysis.

Detection Methods for CVE-2025-13531

Indicators of Compromise

• Unusual JavaScript code present in product name fields within the plugin's database tables
• Unexpected script tags or event handlers (e.g., onerror, onload, onclick) in stored product data
• Browser console errors or unexpected network requests when viewing order form pages
• Reports from users experiencing unexpected redirects or pop-ups when accessing form pages

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect XSS payloads in POST requests targeting the plugin's form endpoints
• Monitor database entries for the presence of HTML tags and JavaScript code in text fields that should contain plain text
• Review WordPress audit logs for suspicious form submissions from Subscriber-level accounts
• Deploy browser-based Content Security Policy (CSP) headers to detect and block inline script execution

Monitoring Recommendations

• Enable detailed logging for all form submissions processed by the Stylish Order Form Builder plugin
• Configure security monitoring tools to alert on patterns consistent with XSS injection attempts
• Regularly audit user accounts with Subscriber privileges for suspicious activity patterns
• Implement real-time alerting for any changes to product records that contain HTML or script content

How to Mitigate CVE-2025-13531

Immediate Actions Required

• Deactivate the Stylish Order Form Builder plugin until a patched version is available
• Audit existing product data in the database for any injected malicious scripts
• Review user accounts with Subscriber-level access for unauthorized or suspicious accounts
• Implement Web Application Firewall rules to filter XSS payloads in form submissions

Patch Information

At the time of publication, no official patch has been confirmed for this vulnerability. Site administrators should monitor the Wordfence Vulnerability Report and the official WordPress plugin repository for security updates. Until a patch is released, the recommended approach is to disable the vulnerable plugin entirely.

Workarounds

• Disable or remove the Stylish Order Form Builder plugin until a security update is available
• Restrict Subscriber-level account registrations and audit existing low-privilege accounts
• Implement Content Security Policy headers to mitigate the impact of any stored XSS payloads
• Use a WAF solution to filter malicious input before it reaches the application

# Add Content Security Policy headers to wp-config.php or .htaccess
# Example Apache .htaccess configuration:
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none';"

# To disable the plugin via WP-CLI:
wp plugin deactivate stylish-order-form-builder