diff --git a/vendor/magento/module-quick-order/view/frontend/web/js/file.js b/vendor/magento/module-quick-order/view/frontend/web/js/file.js
index b13493af43c8..c27281fc29af 100644
--- a/vendor/magento/module-quick-order/view/frontend/web/js/file.js
+++ b/vendor/magento/module-quick-order/view/frontend/web/js/file.js
@@ -68,7 +68,11 @@ define([
                 return;
             }
 
-            if (file.name.split('.').pop() != 'csv') { //eslint-disable-line eqeqeq
+            let allowedMimeTypes = ['text/csv', 'application/vnd.ms-excel', 'text/plain', ''];
+
+            if (file.name.split('.').pop().toLowerCase() !== 'csv' ||
+                allowedMimeTypes.indexOf(file.type) === -1
+            ) {
                 $(this.options.showError).trigger('addErrors', {
                     text: this.options.extErrorText
                 });
@@ -83,11 +87,34 @@ define([
             };
             reader.onload = function (ev) {
                 contents = ev.target.result;
+
+                if (!this._isValidCsvContent(contents)) {
+                    $('body').trigger('processStop');
+                    $(this.options.showError).trigger('addErrors', {
+                        text: this.options.extErrorText
+                    });
+                    this._clearField();
+                    return;
+                }
                 this._displaySkus(contents);
             }.bind(this);
             reader.readAsText(file);
         },
 
+        /**
+         * Check that file content is CSV and its header row contains SKU and QTY columns.
+         *
+         * @param {String} contents
+         * @returns {Boolean}
+         * @private
+         */
+        _isValidCsvContent: function (contents) {
+            var header = contents.split(/[\r\n]+/g)[0] || '';
+
+            return /(^|,)\s*"?sku"?\s*(,|$)/i.test(header) &&
+                /(^|,)\s*"?qty"?\s*(,|$)/i.test(header);
+        },
+
         /**
          * Set SKU name and QTY to list
          *