diff --git a/src/Type/RequestDynamicReturnTypeExtension.php b/src/Type/RequestDynamicReturnTypeExtension.php
index edc2be8..33a1988 100644
--- a/src/Type/RequestDynamicReturnTypeExtension.php
+++ b/src/Type/RequestDynamicReturnTypeExtension.php
@@ -48,16 +48,28 @@ public function getTypeFromMethodCall(
 	): Type
 	{
 		$argument = $methodCall->getArgs()[0] ?? null;
+		$defaultArgument = $methodCall->getArgs()[1] ?? null;
 
-		if ($argument === null || !($argument->value instanceof \PhpParser\Node\Scalar\String_)) {
-			return ParametersAcceptorSelector::selectSingle($methodReflection->getVariants())->getReturnType();
+		if ($argument === null
+			|| !($argument->value instanceof \PhpParser\Node\Scalar\String_)
+			|| !isset($this->requestGetAttributeMapping[$argument->value->value])
+		) {
+			$type = ParametersAcceptorSelector::selectSingle($methodReflection->getVariants())->getReturnType();
+
+			if ($defaultArgument === null) {
+				return $type;
+			}
+
+			return TypeCombinator::union($type, $scope->getType($defaultArgument->value));
 		}
 
-		if (isset($this->requestGetAttributeMapping[$argument->value->value])) {
-			return TypeCombinator::addNull($this->typeStringResolver->resolve($this->requestGetAttributeMapping[$argument->value->value]));
+		$type = $this->typeStringResolver->resolve($this->requestGetAttributeMapping[$argument->value->value]);
+
+		if ($defaultArgument === null) {
+			return TypeCombinator::addNull($type);
 		}
 
-		return ParametersAcceptorSelector::selectSingle($methodReflection->getVariants())->getReturnType();
+		return TypeCombinator::union($type, $scope->getType($defaultArgument->value));
 	}
 
 	public function isMethodSupported(
diff --git a/tests/Unit/Type/data/request-get-attribute-return-types.php b/tests/Unit/Type/data/request-get-attribute-return-types.php
index 8fff231..2847560 100644
--- a/tests/Unit/Type/data/request-get-attribute-return-types.php
+++ b/tests/Unit/Type/data/request-get-attribute-return-types.php
@@ -4,6 +4,7 @@
 
 use Psr\Http\Message\ServerRequestInterface;
 use TYPO3\CMS\Core\Http\NormalizedParams;
+use TYPO3\CMS\Core\Site\Entity\NullSite;
 use TYPO3\CMS\Core\Site\Entity\Site;
 use TYPO3\CMS\Core\Site\Entity\SiteLanguage;
 use function PHPStan\Testing\assertType;
@@ -21,6 +22,7 @@ public function getAttributeTests(ServerRequestInterface $request): void
 		);
 		assertType(SiteLanguage::class . '|null', $request->getAttribute('language'));
 		assertType(Site::class . '|null', $request->getAttribute('site'));
+		assertType(NullSite::class . '|' . Site::class, $request->getAttribute('site', new NullSite()));
 		assertType(NormalizedParams::class . '|null', $request->getAttribute('normalizedParams'));
 		assertType('1|2|4|8|16|null', $request->getAttribute('applicationType'));
 		assertType('FlowdGmbh\\MyProject\\Http\\MyAttribute|null', $request->getAttribute('myCustomAttribute'));