Exploitation Research Plan: CVE-2026-24604 - Simple GDPR Cookie Compliance

1. Vulnerability Summary

The Simple GDPR Cookie Compliance plugin (<= 2.0.0) contains a missing authorization vulnerability. Specifically, an AJAX handler is registered for unauthenticated users (wp_ajax_nopriv_) but fails to verify the caller's capabilities using current_user_can(). This allows unauthenticated attackers to trigger sensitive actions, such as modifying plugin settings or resetting configuration, which are intended for administrators.

2. Attack Vector Analysis

• Endpoint: /wp-admin/admin-ajax.php
• HTTP Method: POST
• Authentication: None (Unauthenticated)
• Action: Likely an AJAX action registered via wp_ajax_nopriv_. Potential candidates include actions related to "saving settings", "resetting data", or "dismissing notices".
• Payload Parameters:
  • action: The vulnerable AJAX action string (e.g., sgcc_save_settings, simple_gdpr_update_options - to be verified).
  • nonce: A security nonce (if required, likely available on the frontend).
  • Data parameters: Parameters representing the settings to be updated (e.g., settings[...]).

3. Code Flow

1. Entry Point: The plugin registers an AJAX action in the main plugin file or an initialization class:

   add_action( 'wp_ajax_nopriv_VULNERABLE_ACTION', 'vulnerable_function_callback' );
   

2. Missing Check: The vulnerable_function_callback is executed. It may call check_ajax_referer() (nonce check) but lacks a check for current_user_can( 'manage_options' ).
3. Data Sink: User-supplied data from $_POST is passed into a function like update_option() or wp_update_post(), leading to unauthorized state changes.

4. Nonce Acquisition Strategy

If the vulnerable function uses check_ajax_referer( 'action_name', 'nonce_key' ), the nonce must be obtained from the frontend.

1. Identify Script Enqueueing: Find where wp_localize_script is called. Look for the localization variable (e.g., sgcc_ajax_obj).
2. Identify Trigger: The plugin likely loads its scripts on the frontend to display the cookie banner.
3. Automated Extraction:
   • Step 1: Navigate to the WordPress homepage using browser_navigate.
   • Step 2: If the scripts don't load on the homepage, check if a specific shortcode is needed (e.g., [gdpr_banner]). If so, create a test page:
     wp post create --post_type=page --post_status=publish --post_content='[target_shortcode]'
   • Step 3: Use browser_eval to extract the nonce:
     browser_eval("window.sgcc_ajax_obj?.nonce") (Replace sgcc_ajax_obj and nonce with actual keys found during discovery).

5. Exploitation Strategy

Phase 1: Discovery

Find the exact AJAX action and parameter names.

1. grep -rn "wp_ajax_nopriv_" wp-content/plugins/simple-gdpr-cookie-compliance/
2. Examine the callback function for calls to update_option.
3. Note the required parameters and the nonce action string.

Phase 2: Execution

Prepare a POST request to admin-ajax.php.

Request Structure (Example - Inferred):

• URL: http://vulnerable-site.local/wp-admin/admin-ajax.php
• Method: POST
• Headers: Content-Type: application/x-www-form-urlencoded
• Body:

  action=VULNERABLE_ACTION&nonce=EXTRACTED_NONCE&settings[banner_text]=<script>alert('XSS')</script>&settings[enabled]=1
  

6. Test Data Setup

1. Plugin Installation: Ensure simple-gdpr-cookie-compliance version <= 2.0.0 is active.
2. Configuration: Use default settings.
3. Shortcode Page: Create a page containing any plugin-specific shortcode to ensure frontend scripts (and nonces) are rendered.

   wp post create --post_title="GDPR Test" --post_content="[simple_gdpr_cookie_compliance]" --post_status="publish" --post_type="page"
   

7. Expected Results

• Success: The server returns a success response (e.g., {"success": true} or 1).
• Impact: Plugin settings are modified. If banner_text was targeted, visiting the homepage will now trigger a JavaScript alert or display modified text.

8. Verification Steps

1. Database Check: Use WP-CLI to verify the option value was changed.

   wp option get simple_gdpr_settings
   

2. Frontend Check: Navigate to the homepage and check for the injected payload in the HTML source.

   # Use browser_navigate to homepage, then check HTML
   

9. Alternative Approaches

• Missing Nonce Check: If check_ajax_referer is absent, the exploit becomes trivial (remove the nonce parameter).
• Settings Reset: If the vulnerability is in a "reset" function (e.g., wp_ajax_nopriv_reset_gdpr), the impact is Availability (wiping plugin config) rather than Integrity (XSS).
• Unsubscribe/Data Export: Check for actions related to user data export or deletion (wp_ajax_nopriv_export_data) which might lead to PII exposure.