diff --git a/connexion/decorators/validation.py b/connexion/decorators/validation.py
index db65dc9..b7c7a62 100644
--- a/connexion/decorators/validation.py
+++ b/connexion/decorators/validation.py
@@ -302,7 +302,11 @@ class ParameterValidator(object):
 
     def validate_formdata_parameter_list(self, request):
         request_params = request.form.keys()
-        spec_params = [x['name'] for x in self.parameters.get('formData', [])]
+        try:
+            spec_params = [x['name'] for x in self.parameters['formData']]
+        except KeyError:
+            # OAS 3
+            return set()
         return validate_parameter_list(request_params, spec_params)
 
     def validate_query_parameter(self, param, request):
diff --git a/tests/api/test_parameters.py b/tests/api/test_parameters.py
index cd2014f..5c9900b 100644
--- a/tests/api/test_parameters.py
+++ b/tests/api/test_parameters.py
@@ -117,6 +117,16 @@ def test_strict_extra_query_param(strict_app):
     assert response['detail'] == "Extra query parameter(s) extra_parameter not in spec"
 
 
+def test_strict_formdata_param(strict_app):
+    app_client = strict_app.app.test_client()
+    headers = {'Content-type': 'application/x-www-form-urlencoded'}
+    url = '/v1.0/test_array_csv_form_param'
+    resp = app_client.post(url, headers=headers, data={"items":"mango"})
+    response = json.loads(resp.data.decode('utf-8', 'replace'))
+    assert response == ['mango']
+    assert resp.status_code == 200
+
+
 def test_path_parameter_someint(simple_app):
     app_client = simple_app.app.test_client()
     resp = app_client.get('/v1.0/test-int-path/123')  # type: flask.Response