diff --git a/src/Symfony/Component/Validator/Constraints/AbstractComparisonValidator.php b/src/Symfony/Component/Validator/Constraints/AbstractComparisonValidator.php
index 7e9934d133..cd96bc9df7 100644
--- a/src/Symfony/Component/Validator/Constraints/AbstractComparisonValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/AbstractComparisonValidator.php
@@ -65,14 +65,14 @@ abstract class AbstractComparisonValidator extends ConstraintValidator
         // This allows to compare with any date/time value supported by
         // the DateTime constructor:
         // https://php.net/datetime.formats
-        if (\is_string($comparedValue)) {
-            if ($value instanceof \DateTimeImmutable) {
-                // If $value is immutable, convert the compared value to a
-                // DateTimeImmutable too
-                $comparedValue = new \DateTimeImmutable($comparedValue);
-            } elseif ($value instanceof \DateTimeInterface) {
-                // Otherwise use DateTime
-                $comparedValue = new \DateTime($comparedValue);
+        if (\is_string($comparedValue) && $value instanceof \DateTimeInterface) {
+            // If $value is immutable, convert the compared value to a DateTimeImmutable too, otherwise use DateTime
+            $dateTimeClass = $value instanceof \DateTimeImmutable ? \DateTimeImmutable::class : \DateTime::class;
+
+            try {
+                $comparedValue = new $dateTimeClass($comparedValue);
+            } catch (\Exception $e) {
+                throw new ConstraintDefinitionException(sprintf('The compared value "%s" could not be converted to a "%s" instance in the "%s" constraint.', $comparedValue, $dateTimeClass, \get_class($constraint)));
             }
         }
 
diff --git a/src/Symfony/Component/Validator/Constraints/RangeValidator.php b/src/Symfony/Component/Validator/Constraints/RangeValidator.php
index c7cb859a5a..ea7d277808 100644
--- a/src/Symfony/Component/Validator/Constraints/RangeValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/RangeValidator.php
@@ -13,6 +13,7 @@ namespace Symfony\Component\Validator\Constraints;
 
 use Symfony\Component\Validator\Constraint;
 use Symfony\Component\Validator\ConstraintValidator;
+use Symfony\Component\Validator\Exception\ConstraintDefinitionException;
 use Symfony\Component\Validator\Exception\UnexpectedTypeException;
 
 /**
@@ -50,12 +51,26 @@ class RangeValidator extends ConstraintValidator
         // the DateTime constructor:
         // https://php.net/datetime.formats
         if ($value instanceof \DateTimeInterface) {
+            $dateTimeClass = null;
+
             if (\is_string($min)) {
-                $min = new \DateTime($min);
+                $dateTimeClass = $value instanceof \DateTimeImmutable ? \DateTimeImmutable::class : \DateTime::class;
+
+                try {
+                    $min = new $dateTimeClass($min);
+                } catch (\Exception $e) {
+                    throw new ConstraintDefinitionException(sprintf('The min value "%s" could not be converted to a "%s" instance in the "%s" constraint.', $min, $dateTimeClass, \get_class($constraint)));
+                }
             }
 
             if (\is_string($max)) {
-                $max = new \DateTime($max);
+                $dateTimeClass = $dateTimeClass ?: ($value instanceof \DateTimeImmutable ? \DateTimeImmutable::class : \DateTime::class);
+
+                try {
+                    $max = new $dateTimeClass($max);
+                } catch (\Exception $e) {
+                    throw new ConstraintDefinitionException(sprintf('The max value "%s" could not be converted to a "%s" instance in the "%s" constraint.', $max, $dateTimeClass, \get_class($constraint)));
+                }
             }
         }
 
diff --git a/src/Symfony/Component/Validator/Tests/Constraints/AbstractComparisonValidatorTestCase.php b/src/Symfony/Component/Validator/Tests/Constraints/AbstractComparisonValidatorTestCase.php
index cb10c06164..b02e57cfa2 100644
--- a/src/Symfony/Component/Validator/Tests/Constraints/AbstractComparisonValidatorTestCase.php
+++ b/src/Symfony/Component/Validator/Tests/Constraints/AbstractComparisonValidatorTestCase.php
@@ -13,6 +13,7 @@ namespace Symfony\Component\Validator\Tests\Constraints;
 
 use Symfony\Component\Intl\Util\IntlTestHelper;
 use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\Constraints\AbstractComparison;
 use Symfony\Component\Validator\Exception\ConstraintDefinitionException;
 use Symfony\Component\Validator\Test\ConstraintValidatorTestCase;
 
@@ -211,6 +212,31 @@ abstract class AbstractComparisonValidatorTestCase extends ConstraintValidatorTe
             ->assertRaised();
     }
 
+    /**
+     * @dataProvider throwsOnInvalidStringDatesProvider
+     */
+    public function testThrowsOnInvalidStringDates(AbstractComparison $constraint, $expectedMessage, $value)
+    {
+        $this->expectException(ConstraintDefinitionException::class);
+        $this->expectExceptionMessage($expectedMessage);
+
+        $this->validator->validate($value, $constraint);
+    }
+
+    public function throwsOnInvalidStringDatesProvider()
+    {
+        $constraint = $this->createConstraint([
+            'value' => 'foo',
+        ]);
+
+        $constraintClass = \get_class($constraint);
+
+        return [
+            [$constraint, sprintf('The compared value "foo" could not be converted to a "DateTimeImmutable" instance in the "%s" constraint.', $constraintClass), new \DateTimeImmutable()],
+            [$constraint, sprintf('The compared value "foo" could not be converted to a "DateTime" instance in the "%s" constraint.', $constraintClass), new \DateTime()],
+        ];
+    }
+
     /**
      * @return array
      */
diff --git a/src/Symfony/Component/Validator/Tests/Constraints/RangeValidatorTest.php b/src/Symfony/Component/Validator/Tests/Constraints/RangeValidatorTest.php
index df33d2c422..83e32d8d97 100644
--- a/src/Symfony/Component/Validator/Tests/Constraints/RangeValidatorTest.php
+++ b/src/Symfony/Component/Validator/Tests/Constraints/RangeValidatorTest.php
@@ -14,6 +14,7 @@ namespace Symfony\Component\Validator\Tests\Constraints;
 use Symfony\Component\Intl\Util\IntlTestHelper;
 use Symfony\Component\Validator\Constraints\Range;
 use Symfony\Component\Validator\Constraints\RangeValidator;
+use Symfony\Component\Validator\Exception\ConstraintDefinitionException;
 use Symfony\Component\Validator\Test\ConstraintValidatorTestCase;
 
 class RangeValidatorTest extends ConstraintValidatorTestCase
@@ -389,4 +390,29 @@ class RangeValidatorTest extends ConstraintValidatorTestCase
             ->setCode(Range::INVALID_CHARACTERS_ERROR)
             ->assertRaised();
     }
+
+    /**
+     * @dataProvider throwsOnInvalidStringDatesProvider
+     */
+    public function testThrowsOnInvalidStringDates($expectedMessage, $value, $min, $max)
+    {
+        $this->expectException(ConstraintDefinitionException::class);
+        $this->expectExceptionMessage($expectedMessage);
+
+        $this->validator->validate($value, new Range([
+            'min' => $min,
+            'max' => $max,
+        ]));
+    }
+
+    public function throwsOnInvalidStringDatesProvider()
+    {
+        return [
+            ['The min value "foo" could not be converted to a "DateTimeImmutable" instance in the "Symfony\Component\Validator\Constraints\Range" constraint.', new \DateTimeImmutable(), 'foo', null],
+            ['The min value "foo" could not be converted to a "DateTime" instance in the "Symfony\Component\Validator\Constraints\Range" constraint.', new \DateTime(), 'foo', null],
+            ['The max value "foo" could not be converted to a "DateTimeImmutable" instance in the "Symfony\Component\Validator\Constraints\Range" constraint.', new \DateTimeImmutable(), null, 'foo'],
+            ['The max value "foo" could not be converted to a "DateTime" instance in the "Symfony\Component\Validator\Constraints\Range" constraint.', new \DateTime(), null, 'foo'],
+            ['The min value "bar" could not be converted to a "DateTimeImmutable" instance in the "Symfony\Component\Validator\Constraints\Range" constraint.', new \DateTimeImmutable(), 'bar', 'ccc'],
+        ];
+    }
 }