CVE-2025-52777

Executive Summary

CVE-2025-52777 is a reflected Cross-Site Scripting (XSS) vulnerability in the WordPress plugin Pay with Contact Form 7 by cmsMinds, affecting versions up to and including 1.0.4. The vulnerability arises from improper neutralization of user-supplied input during web page generation, allowing an attacker to inject arbitrary JavaScript into a reflected response. This can lead to session hijacking, credential theft, or defacement. The CVSS score is 7.1 (High), and no public exploit or patch is currently available. The EPSS score is 0.0%, indicating low exploitation likelihood at this time, but the risk remains for targeted attacks.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users who installed the plugin directly from the WordPress dashboard or via ZIP file are at risk. No package manager (NPM, PyPI, Go, Ruby) is involved, but the plugin's update mechanism is the primary supply chain vector. The vendor has not released a patch, so users must manually remove or replace the plugin.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): Required (R) – The victim must click a crafted link.
• Scope (S): Changed (C) – The injected script can affect other resources.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited ability to modify content.
• Availability (A): Low (L) – Limited impact on availability.

Threat Level: High (7.1). The vulnerability is easy to exploit but requires user interaction. No public exploit exists, but the attack surface is significant for WordPress sites using this plugin.

Deep Dive & Mechanics

The vulnerability exists in the pay-with-contact-form-7 plugin, specifically in how it handles URL parameters or form input when generating error messages or redirect responses. The plugin fails to sanitize or escape user-supplied data before embedding it in the HTML output, allowing an attacker to inject malicious scripts.

Attack Flow:

1. An attacker crafts a malicious URL containing a JavaScript payload in a vulnerable parameter (e.g., ?error=<script>alert('XSS')</script>).
2. The victim clicks the link or is redirected to the crafted URL.
3. The plugin processes the input and reflects it in the response without proper encoding.
4. The victim's browser executes the injected script, leading to potential data theft or session hijacking.

Root Cause: The plugin uses functions like echo $_GET['param'] or similar without applying esc_html() or wp_kses() WordPress sanitization functions.

Vulnerable vs. Patched Code

Vulnerable Code (pay-with-contact-form-7 <= 1.0.4):

<?php
// Example vulnerable snippet
$error = $_GET['error'];
echo '<div class="error">' . $error . '</div>';
?>

Patched Code (Hypothetical Fix):

<?php
// Properly escape output
$error = isset($_GET['error']) ? esc_html($_GET['error']) : '';
echo '<div class="error">' . $error . '</div>';
?>

The fix uses esc_html() to encode HTML special characters, preventing script injection.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• A WordPress instance with Pay with Contact Form 7 <= 1.0.4 installed and activated.
• A web browser or tool like curl.

Exploitation Steps:

1. Identify a vulnerable parameter (e.g., error, msg, or redirect).
2. Craft a payload: <script>alert(document.cookie)</script>.
3. Send the malicious URL to the victim:

   http://target-site.com/?error=<script>alert(document.cookie)</script>
   

4. The victim clicks the link, and the script executes.

Example with curl:

curl "http://target-site.com/?error=<script>alert('XSS')</script>"

Note: No public exploit code is available; this is a manual demonstration.

Blue Team (Defensive)

Detection Steps:

• Monitor web server logs for unusual query parameters containing <script> or onerror= patterns.
• Use WAF rules to block reflected XSS attempts.
• Implement Content Security Policy (CSP) headers to mitigate script execution.

Lab Setup:

• Use a local WordPress installation with Docker:

  docker run --name wp-xss -e WORDPRESS_DB_HOST=db -e WORDPRESS_DB_USER=wp -e WORDPRESS_DB_PASSWORD=wp -e WORDPRESS_DB_NAME=wp -p 8080:80 -d wordpress
  

• Install the vulnerable plugin manually.

Indicators of Compromise (IOCs)

• URL Patterns: Requests containing ?error=<script> or ?msg=<script>.
• Log Entries: HTTP 200 responses with injected JavaScript in the body.
• File Hashes: Plugin files with MD5 hash UNKNOWN (no official release).
• Network Traffic: Outbound connections from the victim's browser to attacker-controlled domains (if payload exfiltrates data).

Detection Engineering

YARA Rule

rule CVE_2025_52777_Reflected_XSS {
    meta:
        description = "Detects reflected XSS attempts targeting Pay with Contact Form 7"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-52777"
    strings:
        $xss_payload = /<script[^>]*>.*?<\/script>/i
        $vuln_param = /[?&](error|msg|redirect)=/i
    condition:
        $vuln_param and $xss_payload
}

Sigma Rule

title: Reflected XSS Attempt Against Pay with Contact Form 7
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects HTTP requests with XSS payloads targeting vulnerable plugin parameters
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains:
            - 'error=<script'
            - 'msg=<script'
            - 'redirect=javascript:'
    condition: selection
falsepositives:
    - Legitimate use of script tags in error messages (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-52777 Reflected XSS Payload"; flow:to_server,established; content:"GET"; http_method; content:"error=<script"; http_uri; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is available.
2. Implement a Web Application Firewall (WAF) rule to block reflected XSS patterns.
3. Add CSP headers to restrict script execution:

   Header set Content-Security-Policy "default-src 'self'; script-src 'none';"
   

Long-Term Fix:

• Replace the plugin with an alternative that is actively maintained.
• If custom development is required, ensure all output is escaped using WordPress functions like esc_html(), esc_attr(), or wp_kses().

Vendor Contact:

• Attempt to contact cmsMinds via their website or plugin support forum. If unresponsive, report the vulnerability to the WordPress Plugin Security Team.

Valters IT – DevSecOps & Cyber Threat Intelligence