diff --git a/vendor/magento/module-customer-graph-ql/Model/Context/AddUserInfoToContext.php b/vendor/magento/module-customer-graph-ql/Model/Context/AddUserInfoToContext.php
index de447a9b8c976..145a098fb5e94 100644
--- a/vendor/magento/module-customer-graph-ql/Model/Context/AddUserInfoToContext.php
+++ b/vendor/magento/module-customer-graph-ql/Model/Context/AddUserInfoToContext.php
@@ -14,6 +14,11 @@
 use Magento\Framework\ObjectManager\ResetAfterRequestInterface;
 use Magento\GraphQl\Model\Query\ContextParametersInterface;
 use Magento\GraphQl\Model\Query\UserContextParametersProcessorInterface;
+use Magento\Framework\App\ObjectManager;
+use Magento\Framework\App\Request\Http as HttpRequest;
+use Magento\Store\Api\Data\StoreInterface;
+use Magento\Store\Model\StoreManagerInterface;
+use Magento\Customer\Model\Config\Share;
 
 /**
  * @SuppressWarnings(PHPMD.CookieAndSessionMisuse)
@@ -40,20 +45,44 @@ class AddUserInfoToContext implements UserContextParametersProcessorInterface, R
      */
     private $customerRepository;
 
+    /**
+     * @var Share
+     */
+    private $configShare;
+
+    /**
+     * @var StoreManagerInterface
+     */
+    private $storeManager;
+
+    /**
+     * @var HttpRequest
+     */
+    private $request;
+
     /**
      * @param UserContextInterface $userContext
      * @param Session $session
      * @param CustomerRepository $customerRepository
+     * @param Share|null $configShare
+     * @param StoreManagerInterface|null $storeManager
+     * @param HttpRequest|null $request
      */
     public function __construct(
         UserContextInterface $userContext,
         Session $session,
-        CustomerRepository $customerRepository
+        CustomerRepository $customerRepository,
+        ?Share $configShare = null,
+        ?StoreManagerInterface $storeManager = null,
+        ?HttpRequest $request = null
     ) {
         $this->userContext = $userContext;
         $this->userContextFromConstructor = $userContext;
         $this->session = $session;
         $this->customerRepository = $customerRepository;
+        $this->configShare = $configShare ?? ObjectManager::getInstance()->get(Share::class);
+        $this->storeManager = $storeManager ?? ObjectManager::getInstance()->get(StoreManagerInterface::class);
+        $this->request = $request ?? ObjectManager::getInstance()->get(HttpRequest::class);
     }
 
     /**
@@ -92,6 +121,13 @@ public function execute(ContextParametersInterface $contextParameters): ContextP
         $isCustomer = $this->isCustomer($currentUserId, $currentUserType);
         $contextParameters->addExtensionAttribute('is_customer', $isCustomer);
 
+        if (!$isCustomer
+            && !empty($currentUserId)
+            && $currentUserType === UserContextInterface::USER_TYPE_CUSTOMER
+        ) {
+            $contextParameters->setUserId(0);
+        }
+
         if ($isCustomer) {
             $customer = $this->customerRepository->getById($currentUserId);
             $this->session->setCustomerData($customer);
@@ -119,8 +155,28 @@ public function getLoggedInCustomerData(): ?CustomerInterface
      */
     private function isCustomer(?int $customerId, ?int $customerType): bool
     {
-        return !empty($customerId)
+        $result = !empty($customerId)
             && !empty($customerType)
             && $customerType === UserContextInterface::USER_TYPE_CUSTOMER;
+
+        if ($result && $this->configShare->isWebsiteScope()) {
+            $customer = $this->customerRepository->getById($customerId);
+            return (int)$customer->getWebsiteId() === (int)$this->getEffectiveStore()->getWebsiteId();
+        }
+        return $result;
+    }
+
+    /**
+     * Resolve the store to use for website-scope validation.
+     *
+     * @return StoreInterface
+     */
+    private function getEffectiveStore(): StoreInterface
+    {
+        $storeCode = trim((string) $this->request->getHeader('Store'));
+        if (!empty($storeCode)) {
+            return $this->storeManager->getStore($storeCode);
+        }
+        return $this->storeManager->getStore();
     }
 }