diff --git a/vendor/magento/module-checkout/Controller/Cart/CouponPost.php b/vendor/magento/module-checkout/Controller/Cart/CouponPost.php
index fdfe817f354f..7b56ab223d1f 100644
--- a/vendor/magento/module-checkout/Controller/Cart/CouponPost.php
+++ b/vendor/magento/module-checkout/Controller/Cart/CouponPost.php
@@ -20,8 +20,6 @@ class CouponPost extends \Magento\Checkout\Controller\Cart implements HttpPostAc
     protected $quoteRepository;

     /**
-     * Coupon factory
-     *
      * @var \Magento\SalesRule\Model\CouponFactory
      */
     protected $couponFactory;
@@ -70,10 +68,10 @@ public function execute()
     {
         $couponCode = $this->getRequest()->getParam('remove') == 1
             ? ''
-            : trim($this->getRequest()->getParam('coupon_code'));
+            : trim($this->getRequest()->getParam('coupon_code', ''));

         $cartQuote = $this->cart->getQuote();
-        $oldCouponCode = $cartQuote->getCouponCode();
+        $oldCouponCode = $cartQuote->getCouponCode() ?? '';

         $codeLength = strlen($couponCode);
         if (!$codeLength && !strlen($oldCouponCode)) {