diff --git a/authlib/oauth2/rfc7592/endpoint.py b/authlib/oauth2/rfc7592/endpoint.py
index cec9aad1..25d8b6ab 100644
--- a/authlib/oauth2/rfc7592/endpoint.py
+++ b/authlib/oauth2/rfc7592/endpoint.py
@@ -136,7 +136,10 @@ def _validate_scope(claims, value):
             response_types_supported = set(response_types_supported)
 
             def _validate_response_types(claims, value):
-                return response_types_supported.issuperset(set(value))
+                # If omitted, the default is that the client will use only the "code"
+                # response type.
+                response_types = set(value) if value else {"code"}
+                return response_types_supported.issuperset(response_types)
 
             options['response_types'] = {'validate': _validate_response_types}
 
@@ -144,7 +147,10 @@ def _validate_response_types(claims, value):
             grant_types_supported = set(grant_types_supported)
 
             def _validate_grant_types(claims, value):
-                return grant_types_supported.issuperset(set(value))
+                # If omitted, the default behavior is that the client will use only
+                # the "authorization_code" Grant Type.
+                grant_types = set(value) if value else {"authorization_code"}
+                return grant_types_supported.issuperset(grant_types)
 
             options['grant_types'] = {'validate': _validate_grant_types}
 
diff --git a/tests/flask/test_oauth2/test_client_configuration_endpoint.py b/tests/flask/test_oauth2/test_client_configuration_endpoint.py
index 661a8f4b..0cc2da14 100644
--- a/tests/flask/test_oauth2/test_client_configuration_endpoint.py
+++ b/tests/flask/test_oauth2/test_client_configuration_endpoint.py
@@ -21,7 +21,7 @@ def authenticate_token(self, request):
             return Token.query.filter_by(access_token=access_token).first()
 
     def update_client(self, client, client_metadata, request):
-        client.set_client_metadata({**client.client_metadata, **client_metadata})
+        client.set_client_metadata(client_metadata)
         db.session.add(client)
         db.session.commit()
         return client
@@ -195,7 +195,7 @@ def test_update_client(self):
         self.assertEqual(resp['client_id'], client.client_id)
         self.assertEqual(resp['client_name'], 'NewAuthlib')
         self.assertEqual(client.client_name, 'NewAuthlib')
-        self.assertEqual(client.scope, 'openid profile')
+        self.assertEqual(client.scope, '')
 
     def test_access_denied(self):
         user, client, token = self.prepare_data()
@@ -382,6 +382,16 @@ def test_response_types_supported(self):
         self.assertEqual(resp['client_name'], 'Authlib')
         self.assertEqual(resp['response_types'], ['code'])
 
+        # https://datatracker.ietf.org/doc/html/rfc7592#section-2.2
+        # If omitted, the default is that the client will use only the "code"
+        # response type.
+        body = {'client_id': 'client_id', 'client_name': 'Authlib'}
+        rv = self.client.put('/configure_client/client_id', json=body, headers=headers)
+        resp = json.loads(rv.data)
+        self.assertIn('client_id', resp)
+        self.assertEqual(resp['client_name'], 'Authlib')
+        self.assertNotIn('response_types', resp)
+
         body = {
             'client_id': 'client_id',
             'response_types': ['code', 'token'],
@@ -407,6 +417,16 @@ def test_grant_types_supported(self):
         self.assertEqual(resp['client_name'], 'Authlib')
         self.assertEqual(resp['grant_types'], ['password'])
 
+        # https://datatracker.ietf.org/doc/html/rfc7592#section-2.2
+        # If omitted, the default behavior is that the client will use only
+        # the "authorization_code" Grant Type.
+        body = {'client_id': 'client_id', 'client_name': 'Authlib'}
+        rv = self.client.put('/configure_client/client_id', json=body, headers=headers)
+        resp = json.loads(rv.data)
+        self.assertIn('client_id', resp)
+        self.assertEqual(resp['client_name'], 'Authlib')
+        self.assertNotIn('grant_types', resp)
+
         body = {
             'client_id': 'client_id',
             'grant_types': ['client_credentials'],