Normalize new line symbols in Product Text Option (type=area)

app/code/Magento/Catalog/Model/Product/Option/Type/Text.php

@@ -10,6 +10,8 @@
 
 /**
  * Catalog product option text type
+ *
+ * @SuppressWarnings(PHPMD.CookieAndSessionMisuse)
  */
 class Text extends \Magento\Catalog\Model\Product\Option\Type\DefaultType
 {
@@ -68,6 +70,7 @@ public function validateUserValue($values)
 
         // Check maximal length limit
         $maxCharacters = $option->getMaxCharacters();
+        $value = $this->normalizeNewLineSymbols($value);
         if ($maxCharacters > 0 && $this->string->strlen($value) > $maxCharacters) {
             $this->setIsValid(false);
             throw new LocalizedException(__('The text is too long. Shorten the text and try again.'));
@@ -101,4 +104,15 @@ public function getFormattedOptionValue($value)
     {
         return $this->_escaper->escapeHtml($value);
     }
+
+    /**
+     * Normalize newline symbols
+     *
+     * @param string $value
+     * @return string
+     */
+    private function normalizeNewLineSymbols(string $value)
+    {
+        return str_replace(["\r\n", "\n\r", "\r"], "\n", $value);
+    }
 }

dev/tests/integration/testsuite/Magento/Catalog/Model/Product/Option/Type/TextTest.php

@@ -0,0 +1,79 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+namespace Magento\Catalog\Model\Product\Option\Type;
+
+use Magento\Catalog\Model\Product\Option;
+use Magento\Framework\ObjectManagerInterface;
+use Magento\TestFramework\Helper\Bootstrap;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Test for customizable product option with "Text" type
+ */
+class TextTest extends TestCase
+{
+    const STUB_OPTION_DATA = ['id' => 11, 'type' => 'area'];
+
+    /**
+     * @var Text
+     */
+    protected $optionText;
+
+    /**
+     * @var ObjectManagerInterface
+     */
+    private $objectManager;
+
+    /**
+     * {@inheritDoc}
+     */
+    protected function setUp()
+    {
+        $this->objectManager = Bootstrap::getObjectManager();
+        $this->optionText = $this->objectManager->create(Text::class);
+    }
+
+    /**
+     * Check if newline symbols are normalized in option value
+     *
+     * @dataProvider optionValueDataProvider
+     * @param array $productOptionData
+     * @param string $optionValue
+     * @param string $expectedOptionValue
+     */
+    public function testNormalizeNewlineSymbols(
+        array $productOptionData,
+        string $optionValue,
+        string $expectedOptionValue
+    ) {
+        $productOption = $this->objectManager->create(
+            Option::class,
+            ['data' => $productOptionData]
+        );
+
+        $this->optionText->setOption($productOption);
+        $this->optionText->setUserValue($optionValue);
+        $this->optionText->validateUserValue([]);
+
+        $this->assertSame($expectedOptionValue, $this->optionText->getUserValue());
+    }
+
+    /**
+     * Data provider for testNormalizeNewlineSymbols
+     *
+     * @return array
+     */
+    public function optionValueDataProvider()
+    {
+        return [
+            [self::STUB_OPTION_DATA, 'string string', 'string string'],
+            [self::STUB_OPTION_DATA, "string \r\n string", "string \n string"],
+            [self::STUB_OPTION_DATA, "string \n\r string", "string \n string"],
+            [self::STUB_OPTION_DATA, "string \r string", "string \n string"]
+        ];
+    }
+}