diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index dd0876323e3..c4c10132275 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -11,6 +11,7 @@
         <server name="KERNEL_DIR" value="tests/Fixtures/app/" />
         <server name="KERNEL_CLASS" value="AppKernel" />
         <env name="APP_ENV" value="test" />
+        <env name="SYMFONY_PHPUNIT_REQUIRE" value="nikic/php-parser:^4.16"/>
     </php>
 
     <testsuites>
diff --git a/src/Serializer/AbstractItemNormalizer.php b/src/Serializer/AbstractItemNormalizer.php
index 9e7f9aa21f8..837f67ceae7 100644
--- a/src/Serializer/AbstractItemNormalizer.php
+++ b/src/Serializer/AbstractItemNormalizer.php
@@ -630,9 +630,10 @@ protected function getFactoryOptions(array $context): array
             $options['serializer_groups'] = (array) $context[self::GROUPS];
         }
 
-        $operationCacheKey = ($context['resource_class'] ?? '').($context['operation_name'] ?? '').($context['api_normalize'] ?? '');
-        if ($operationCacheKey && isset($this->localFactoryOptionsCache[$operationCacheKey])) {
-            return $options + $this->localFactoryOptionsCache[$operationCacheKey];
+        $operationCacheKey = ($context['resource_class'] ?? '').($context['operation_name'] ?? '').($context['root_operation_name'] ?? '');
+        $suffix = ($context['api_normalize'] ?? '') ? 'n' : '';
+        if ($operationCacheKey && isset($this->localFactoryOptionsCache[$operationCacheKey.$suffix])) {
+            return $options + $this->localFactoryOptionsCache[$operationCacheKey.$suffix];
         }
 
         // This is a hot spot
@@ -645,7 +646,7 @@ protected function getFactoryOptions(array $context): array
             }
         }
 
-        return $options + $this->localFactoryOptionsCache[$operationCacheKey] = $options;
+        return $options + $this->localFactoryOptionsCache[$operationCacheKey.$suffix] = $options;
     }
 
     /**
diff --git a/src/Serializer/Tests/AbstractItemNormalizerTest.php b/src/Serializer/Tests/AbstractItemNormalizerTest.php
index 9766c01ee07..f873a49bfe7 100644
--- a/src/Serializer/Tests/AbstractItemNormalizerTest.php
+++ b/src/Serializer/Tests/AbstractItemNormalizerTest.php
@@ -1545,6 +1545,84 @@ public function testDenormalizeObjectWithNullDisabledTypeEnforcement(): void
         $this->assertInstanceOf(DtoWithNullValue::class, $actual);
         $this->assertEquals(new DtoWithNullValue(), $actual);
     }
+
+    public function testCacheKey(): void
+    {
+        $relatedDummy = new RelatedDummy();
+
+        $dummy = new Dummy();
+        $dummy->setName('foo');
+        $dummy->setAlias('ignored');
+        $dummy->setRelatedDummy($relatedDummy);
+        $dummy->relatedDummies->add(new RelatedDummy());
+
+        $relatedDummies = new ArrayCollection([$relatedDummy]);
+
+        $propertyNameCollectionFactoryProphecy = $this->prophesize(PropertyNameCollectionFactoryInterface::class);
+        $propertyNameCollectionFactoryProphecy->create(Dummy::class, Argument::type('array'))->willReturn(new PropertyNameCollection(['name', 'alias', 'relatedDummy', 'relatedDummies']));
+
+        $relatedDummyType = new Type(Type::BUILTIN_TYPE_OBJECT, false, RelatedDummy::class);
+        $relatedDummiesType = new Type(Type::BUILTIN_TYPE_OBJECT, false, ArrayCollection::class, true, new Type(Type::BUILTIN_TYPE_INT), $relatedDummyType);
+
+        $propertyMetadataFactoryProphecy = $this->prophesize(PropertyMetadataFactoryInterface::class);
+        $propertyMetadataFactoryProphecy->create(Dummy::class, 'name', Argument::type('array'))->willReturn((new ApiProperty())->withBuiltinTypes([new Type(Type::BUILTIN_TYPE_STRING)])->withDescription('')->withReadable(true));
+        $propertyMetadataFactoryProphecy->create(Dummy::class, 'alias', Argument::type('array'))->willReturn((new ApiProperty())->withBuiltinTypes([new Type(Type::BUILTIN_TYPE_STRING)])->withDescription('')->withReadable(true));
+        $propertyMetadataFactoryProphecy->create(Dummy::class, 'relatedDummy', Argument::type('array'))->willReturn((new ApiProperty())->withBuiltinTypes([$relatedDummyType])->withDescription('')->withReadable(true)->withWritable(false)->withReadableLink(false));
+        $propertyMetadataFactoryProphecy->create(Dummy::class, 'relatedDummies', Argument::type('array'))->willReturn((new ApiProperty())->withBuiltinTypes([$relatedDummiesType])->withReadable(true)->withWritable(false)->withReadableLink(false));
+
+        $iriConverterProphecy = $this->prophesize(IriConverterInterface::class);
+        $iriConverterProphecy->getIriFromResource($dummy, Argument::cetera())->willReturn('/dummies/1');
+        $iriConverterProphecy->getIriFromResource($relatedDummy, Argument::cetera())->willReturn('/dummies/2');
+
+        $propertyAccessorProphecy = $this->prophesize(PropertyAccessorInterface::class);
+        $propertyAccessorProphecy->getValue($dummy, 'name')->willReturn('foo');
+        $propertyAccessorProphecy->getValue($dummy, 'relatedDummy')->willReturn($relatedDummy);
+        $propertyAccessorProphecy->getValue($dummy, 'relatedDummies')->willReturn($relatedDummies);
+
+        $resourceClassResolverProphecy = $this->prophesize(ResourceClassResolverInterface::class);
+        $resourceClassResolverProphecy->getResourceClass(null, Dummy::class)->willReturn(Dummy::class);
+        $resourceClassResolverProphecy->getResourceClass($dummy, null)->willReturn(Dummy::class);
+        $resourceClassResolverProphecy->getResourceClass($relatedDummy, RelatedDummy::class)->willReturn(RelatedDummy::class);
+        $resourceClassResolverProphecy->getResourceClass($relatedDummies, RelatedDummy::class)->willReturn(RelatedDummy::class);
+        $resourceClassResolverProphecy->isResourceClass(Dummy::class)->willReturn(true);
+        $resourceClassResolverProphecy->isResourceClass(RelatedDummy::class)->willReturn(true);
+
+        $serializerProphecy = $this->prophesize(SerializerInterface::class);
+        $serializerProphecy->willImplement(NormalizerInterface::class);
+        $serializerProphecy->normalize('foo', null, Argument::type('array'))->willReturn('foo');
+        $serializerProphecy->normalize(['/dummies/2'], null, Argument::type('array'))->willReturn(['/dummies/2']);
+
+        $normalizer = $this->getMockForAbstractClass(AbstractItemNormalizer::class, [
+            $propertyNameCollectionFactoryProphecy->reveal(),
+            $propertyMetadataFactoryProphecy->reveal(),
+            $iriConverterProphecy->reveal(),
+            $resourceClassResolverProphecy->reveal(),
+            $propertyAccessorProphecy->reveal(),
+            null,
+            null,
+            [],
+            null,
+            null,
+        ]);
+        $normalizer->setSerializer($serializerProphecy->reveal());
+
+        $expected = [
+            'name' => 'foo',
+            'relatedDummy' => '/dummies/2',
+            'relatedDummies' => ['/dummies/2'],
+        ];
+        $this->assertSame($expected, $normalizer->normalize($dummy, null, [
+            'resources' => [],
+            'groups' => ['group'],
+            'ignored_attributes' => ['alias'],
+            'operation_name' => 'operation_name',
+            'root_operation_name' => 'root_operation_name',
+        ]));
+
+        $operationCacheKey = (new \ReflectionClass($normalizer))->getProperty('localFactoryOptionsCache')->getValue($normalizer);
+        $this->assertEquals(array_keys($operationCacheKey), [sprintf('%s%s%s%s', Dummy::class, 'operation_name', 'root_operation_name', 'n')]);
+        $this->assertEquals(current($operationCacheKey), ['serializer_groups' => ['group']]);
+    }
 }
 
 class ObjectWithBasicProperties
diff --git a/src/State/Provider/ContentNegotiationProvider.php b/src/State/Provider/ContentNegotiationProvider.php
index 8b3cb533ff8..05da2a02b65 100644
--- a/src/State/Provider/ContentNegotiationProvider.php
+++ b/src/State/Provider/ContentNegotiationProvider.php
@@ -97,7 +97,8 @@ private function flattenMimeTypes(array $formats): array
      */
     private function getInputFormat(HttpOperation $operation, Request $request): ?string
     {
-        if (null === ($contentType = $request->headers->get('CONTENT_TYPE'))) {
+        $contentType = $request->headers->get('CONTENT_TYPE');
+        if (null === $contentType || '' === $contentType) {
             return null;
         }
 
diff --git a/src/State/Provider/DeserializeProvider.php b/src/State/Provider/DeserializeProvider.php
index b2217275051..09a3f7b7f51 100644
--- a/src/State/Provider/DeserializeProvider.php
+++ b/src/State/Provider/DeserializeProvider.php
@@ -56,7 +56,7 @@ public function provide(Operation $operation, array $uriVariables = [], array $c
         }
 
         $contentType = $request->headers->get('CONTENT_TYPE');
-        if (null === $contentType) {
+        if (null === $contentType || '' === $contentType) {
             throw new UnsupportedMediaTypeHttpException('The "Content-Type" header must exist.');
         }
 
diff --git a/src/Symfony/EventListener/DeserializeListener.php b/src/Symfony/EventListener/DeserializeListener.php
index a246ad9fef3..00b53ec42eb 100644
--- a/src/Symfony/EventListener/DeserializeListener.php
+++ b/src/Symfony/EventListener/DeserializeListener.php
@@ -132,7 +132,7 @@ private function getFormat(Request $request, array $formats): string
     {
         /** @var ?string $contentType */
         $contentType = $request->headers->get('CONTENT_TYPE');
-        if (null === $contentType) {
+        if (null === $contentType || '' === $contentType) {
             throw new UnsupportedMediaTypeHttpException('The "Content-Type" header must exist.');
         }
 
diff --git a/tests/State/Provider/ContentNegotiationProviderTest.php b/tests/State/Provider/ContentNegotiationProviderTest.php
new file mode 100644
index 00000000000..e4eb99ba904
--- /dev/null
+++ b/tests/State/Provider/ContentNegotiationProviderTest.php
@@ -0,0 +1,63 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Tests\State\Provider;
+
+use ApiPlatform\Metadata\Post;
+use ApiPlatform\State\Provider\ContentNegotiationProvider;
+use ApiPlatform\State\ProviderInterface;
+use Negotiation\Negotiator;
+use PHPUnit\Framework\TestCase;
+use Prophecy\Argument;
+use Prophecy\PhpUnit\ProphecyTrait;
+use Symfony\Component\HttpFoundation\Request;
+
+class ContentNegotiationProviderTest extends TestCase
+{
+    use ProphecyTrait;
+
+    public function testRequestWithEmptyContentType(): void
+    {
+        $expectedResult = new \stdClass();
+
+        $decorated = $this->prophesize(ProviderInterface::class);
+        $decorated->provide(Argument::cetera())->willReturn($expectedResult);
+
+        $negotiator = new Negotiator();
+        $formats = ['jsonld' => ['application/ld+json']];
+        $errorFormats = ['jsonld' => ['application/ld+json']];
+
+        $provider = new ContentNegotiationProvider($decorated->reveal(), $negotiator, $formats, $errorFormats);
+
+        // in Symfony (at least up to 7.0.2, 6.4.2, 6.3.11, 5.4.34), a request
+        // without a content-type and content-length header will result in the
+        // variables set to an empty string, not null
+
+        $request = new Request(
+            server: [
+                'REQUEST_METHOD' => 'POST',
+                'REQUEST_URI' => '/',
+                'CONTENT_TYPE' => '',
+                'CONTENT_LENGTH' => '',
+            ],
+            content: ''
+        );
+
+        $operation = new Post();
+        $context = ['request' => $request];
+
+        $result = $provider->provide($operation, [], $context);
+
+        $this->assertSame($expectedResult, $result);
+    }
+}
diff --git a/tests/State/Provider/DeserializeProviderTest.php b/tests/State/Provider/DeserializeProviderTest.php
new file mode 100644
index 00000000000..b94c7473ca9
--- /dev/null
+++ b/tests/State/Provider/DeserializeProviderTest.php
@@ -0,0 +1,63 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Tests\State\Provider;
+
+use ApiPlatform\Metadata\Post;
+use ApiPlatform\Serializer\SerializerContextBuilderInterface;
+use ApiPlatform\State\Provider\DeserializeProvider;
+use ApiPlatform\State\ProviderInterface;
+use PHPUnit\Framework\TestCase;
+use Prophecy\Argument;
+use Prophecy\PhpUnit\ProphecyTrait;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\Exception\UnsupportedMediaTypeHttpException;
+use Symfony\Component\Serializer\SerializerInterface;
+
+class DeserializeProviderTest extends TestCase
+{
+    use ProphecyTrait;
+
+    public function testRequestWithEmptyContentType(): void
+    {
+        $expectedResult = new \stdClass();
+
+        $decorated = $this->prophesize(ProviderInterface::class);
+        $decorated->provide(Argument::cetera())->willReturn($expectedResult);
+
+        $serializer = $this->prophesize(SerializerInterface::class);
+        $serializerContextBuilder = $this->prophesize(SerializerContextBuilderInterface::class);
+
+        $provider = new DeserializeProvider($decorated->reveal(), $serializer->reveal(), $serializerContextBuilder->reveal());
+
+        // in Symfony (at least up to 7.0.2, 6.4.2, 6.3.11, 5.4.34), a request
+        // without a content-type and content-length header will result in the
+        // variables set to an empty string, not null
+
+        $request = new Request(
+            server: [
+                'REQUEST_METHOD' => 'POST',
+                'REQUEST_URI' => '/',
+                'CONTENT_TYPE' => '',
+                'CONTENT_LENGTH' => '',
+            ],
+            content: ''
+        );
+
+        $operation = new Post(deserialize: true);
+        $context = ['request' => $request];
+
+        $this->expectException(UnsupportedMediaTypeHttpException::class);
+        $result = $provider->provide($operation, [], $context);
+    }
+}
diff --git a/tests/Symfony/EventListener/DeserializeListenerTest.php b/tests/Symfony/EventListener/DeserializeListenerTest.php
index 8290d47b801..f12489bb6e0 100644
--- a/tests/Symfony/EventListener/DeserializeListenerTest.php
+++ b/tests/Symfony/EventListener/DeserializeListenerTest.php
@@ -28,6 +28,7 @@
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Event\RequestEvent;
 use Symfony\Component\HttpKernel\Exception\UnsupportedMediaTypeHttpException;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
 use Symfony\Component\Serializer\Exception\NotNormalizableValueException;
 use Symfony\Component\Serializer\Exception\PartialDenormalizationException;
 use Symfony\Component\Serializer\Normalizer\AbstractNormalizer;
@@ -369,4 +370,56 @@ public function testTurnPartialDenormalizationExceptionIntoValidationException()
             $this->assertSame($violation->getCode(), 'ba785a8c-82cb-4283-967c-3cf342181b40');
         }
     }
+
+    public function testRequestWithEmptyContentType(): void
+    {
+        $serializerProphecy = $this->prophesize(SerializerInterface::class);
+        $serializerProphecy->deserialize(Argument::cetera())->shouldNotBeCalled();
+
+        $serializerContextBuilderProphecy = $this->prophesize(SerializerContextBuilderInterface::class);
+        $serializerContextBuilderProphecy->createFromRequest(Argument::cetera())->willReturn([]);
+
+        $resourceMetadataFactoryProphecy = $this->prophesize(ResourceMetadataCollectionFactoryInterface::class);
+        $resourceMetadataFactoryProphecy->create(Argument::cetera())->willReturn(new ResourceMetadataCollection(Dummy::class, [
+            new ApiResource(operations: [
+                'post' => new Post(inputFormats: self::FORMATS),
+            ]),
+        ]))->shouldBeCalled();
+
+        $listener = new DeserializeListener(
+            $serializerProphecy->reveal(),
+            $serializerContextBuilderProphecy->reveal(),
+            $resourceMetadataFactoryProphecy->reveal()
+        );
+
+        // in Symfony (at least up to 7.0.2, 6.4.2, 6.3.11, 5.4.34), a request
+        // without a content-type and content-length header will result in the
+        // variables set to an empty string, not null
+
+        $request = new Request(
+            server: [
+                'REQUEST_METHOD' => 'POST',
+                'REQUEST_URI' => '/',
+                'CONTENT_TYPE' => '',
+                'CONTENT_LENGTH' => '',
+            ],
+            attributes: [
+                '_api_resource_class' => Dummy::class,
+                '_api_operation_name' => 'post',
+                '_api_receive' => true,
+            ],
+            content: ''
+        );
+
+        $event = new RequestEvent(
+            $this->prophesize(HttpKernelInterface::class)->reveal(),
+            $request,
+            \defined(HttpKernelInterface::class.'::MAIN_REQUEST') ? HttpKernelInterface::MAIN_REQUEST : HttpKernelInterface::MASTER_REQUEST,
+        );
+
+        $this->expectException(UnsupportedMediaTypeHttpException::class);
+        $this->expectExceptionMessage('The "Content-Type" header must exist.');
+
+        $listener->onKernelRequest($event);
+    }
 }