CVE-2025-23623: Contact Form 7 CCAvenue Add-on XSS Flaw

CVE-2025-23623 Overview

CVE-2025-23623 is a Reflected Cross-Site Scripting (XSS) vulnerability affecting the Contact Form 7 – CCAvenue Add-on WordPress plugin developed by Mahesh Bisen. This vulnerability stems from improper neutralization of user-supplied input during web page generation, allowing attackers to inject malicious scripts that execute in the context of a victim's browser session.

The vulnerability enables attackers to craft malicious URLs containing JavaScript payloads. When a victim clicks on such a link, the injected script executes within their browser, potentially leading to session hijacking, credential theft, or further attacks against the WordPress installation.

Critical Impact

This Reflected XSS vulnerability can be exploited remotely without authentication, potentially compromising WordPress administrator sessions and enabling full site takeover.

Affected Products

• Contact Form 7 – CCAvenue Add-on (cf7-cc-avenue-add-on) version 1.0 and earlier
• WordPress installations using the affected plugin
• Sites integrating CCAvenue payment gateway with Contact Form 7

Discovery Timeline

• 2025-01-16 - CVE-2025-23623 published to NVD
• 2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-23623

Vulnerability Analysis

This vulnerability falls under CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The Contact Form 7 – CCAvenue Add-on fails to properly sanitize and escape user-controlled input before reflecting it back in the HTTP response.

Reflected XSS vulnerabilities require social engineering to exploit, as victims must be tricked into clicking a malicious link. However, the network-accessible attack vector and lack of authentication requirements make this vulnerability particularly concerning for public-facing WordPress sites.

The impact includes potential compromise of confidentiality, integrity, and availability of the web application. Attackers can steal session cookies, modify page content, redirect users to malicious sites, or perform actions on behalf of authenticated users including administrators.

Root Cause

The root cause of this vulnerability is insufficient input validation and output encoding within the cf7-cc-avenue-add-on plugin. User-supplied data is reflected in the page response without proper HTML entity encoding or JavaScript escaping, allowing malicious script tags or event handlers to be injected and executed by the browser.

WordPress plugins that handle payment gateway integrations often process numerous URL parameters, and failure to sanitize any single parameter can introduce XSS vulnerabilities. In this case, the plugin does not properly apply WordPress security functions like esc_html(), esc_attr(), or wp_kses() to user input before output.

Attack Vector

The attack is executed via the network layer, requiring an attacker to craft a malicious URL containing the XSS payload and convince a victim to click the link. This is typically accomplished through phishing emails, malicious advertisements, or compromised websites.

The attacker would construct a URL targeting the affected plugin's functionality with embedded JavaScript. When a logged-in WordPress administrator clicks the link, the script executes with their session privileges. This could allow the attacker to create new admin accounts, install malicious plugins, or exfiltrate sensitive data.

Since no authentication or special privileges are required by the attacker to craft the malicious payload, the barrier to exploitation is low. The primary requirement is user interaction (clicking the malicious link), which makes social engineering a key component of successful exploitation.

Detection Methods for CVE-2025-23623

Indicators of Compromise

• Unusual URL parameters containing encoded JavaScript in web server access logs targeting the cf7-cc-avenue-add-on plugin endpoints
• Browser console errors or unexpected script execution on pages utilizing Contact Form 7 with CCAvenue integration
• Reports from users about suspicious redirects or pop-ups when interacting with contact forms
• Web Application Firewall (WAF) alerts for XSS patterns in request parameters

Detection Strategies

• Deploy Web Application Firewall rules to detect and block common XSS payloads in URL parameters and form submissions
• Implement Content Security Policy (CSP) headers to prevent inline script execution and restrict script sources
• Monitor WordPress access logs for requests to plugin endpoints containing suspicious characters such as <script>, javascript:, or event handlers like onerror
• Use browser-based XSS detection tools and security scanners to test for reflected input in responses

Monitoring Recommendations

• Enable WordPress security logging plugins to track suspicious activity and failed authentication attempts
• Configure real-time alerting for WAF rule triggers related to XSS patterns targeting WordPress plugin paths
• Regularly audit installed plugins for known vulnerabilities using WordPress security scanners or services like Patchstack

How to Mitigate CVE-2025-23623

Immediate Actions Required

• Remove or deactivate the Contact Form 7 – CCAvenue Add-on plugin (cf7-cc-avenue-add-on) immediately until a patched version is available
• Review server access logs for evidence of exploitation attempts targeting the plugin
• Implement Web Application Firewall rules to block XSS payloads targeting the affected plugin endpoints
• Consider alternative CCAvenue integration solutions that are actively maintained and security audited

Patch Information

As of the published CVE data, all versions of the Contact Form 7 – CCAvenue Add-on through version 1.0 are affected. Check the Patchstack Vulnerability Report for the latest remediation guidance and patch availability.

Contact the plugin developer Mahesh Bisen for information regarding patched releases. If no update is available, consider removing the plugin and migrating to a secure alternative.

Workarounds

• Implement strict Content Security Policy headers to mitigate the impact of successful XSS exploitation
• Use a Web Application Firewall with XSS protection rulesets to filter malicious requests before they reach the application
• Restrict plugin access to authenticated users only through WordPress capability checks or access control plugins
• Apply input validation and output encoding manually by creating a child plugin wrapper if source code modification is feasible

# Example: Apache .htaccess rules to block common XSS patterns
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{QUERY_STRING} (<|%3C).*script.*(>|%3E) [NC,OR]
    RewriteCond %{QUERY_STRING} javascript: [NC,OR]
    RewriteCond %{QUERY_STRING} (onmouseover|onerror|onclick)= [NC]
    RewriteRule .* - [F,L]
</IfModule>