diff --git a/openapi_core/templating/media_types/finders.py b/openapi_core/templating/media_types/finders.py
index 3425be96..89a379ba 100644
--- a/openapi_core/templating/media_types/finders.py
+++ b/openapi_core/templating/media_types/finders.py
@@ -8,13 +8,13 @@ class MediaTypeFinder:
     def __init__(self, content):
         self.content = content
 
-    def find(self, request):
-        if request.mimetype in self.content:
-            return self.content / request.mimetype, request.mimetype
+    def find(self, mimetype):
+        if mimetype in self.content:
+            return self.content / mimetype, mimetype
 
-        if request.mimetype:
+        if mimetype:
             for key, value in self.content.items():
-                if fnmatch.fnmatch(request.mimetype, key):
+                if fnmatch.fnmatch(mimetype, key):
                     return value, key
 
-        raise MediaTypeNotFound(request.mimetype, list(self.content.keys()))
+        raise MediaTypeNotFound(mimetype, list(self.content.keys()))
diff --git a/openapi_core/validation/request/validators.py b/openapi_core/validation/request/validators.py
index 4b44016c..2c42d92d 100644
--- a/openapi_core/validation/request/validators.py
+++ b/openapi_core/validation/request/validators.py
@@ -139,7 +139,7 @@ def _get_body(self, request, operation):
 
         try:
             media_type, mimetype = self._get_media_type(
-                request_body / "content", request
+                request_body / "content", request.mimetype
             )
         except MediaTypeFinderError as exc:
             return None, [exc]
diff --git a/openapi_core/validation/response/validators.py b/openapi_core/validation/response/validators.py
index 897ca077..17804cf4 100644
--- a/openapi_core/validation/response/validators.py
+++ b/openapi_core/validation/response/validators.py
@@ -48,7 +48,7 @@ def _get_data(self, response, operation_response):
 
         try:
             media_type, mimetype = self._get_media_type(
-                operation_response / "content", response
+                operation_response / "content", response.mimetype
             )
         except MediaTypeFinderError as exc:
             return None, [exc]
diff --git a/openapi_core/validation/validators.py b/openapi_core/validation/validators.py
index 280ac82e..87cf7979 100644
--- a/openapi_core/validation/validators.py
+++ b/openapi_core/validation/validators.py
@@ -51,11 +51,11 @@ def schema_unmarshallers_factory(self):
     def _find_path(self, request):
         return self.path_finder.find(request)
 
-    def _get_media_type(self, content, request_or_response):
+    def _get_media_type(self, content, mimetype):
         from openapi_core.templating.media_types.finders import MediaTypeFinder
 
         finder = MediaTypeFinder(content)
-        return finder.find(request_or_response)
+        return finder.find(mimetype)
 
     def _deserialise_data(self, mimetype, value):
         deserializer = self.media_type_deserializers_factory.create(mimetype)
diff --git a/tests/unit/templating/test_media_types_finders.py b/tests/unit/templating/test_media_types_finders.py
index 4c1fe9ef..d71260f6 100644
--- a/tests/unit/templating/test_media_types_finders.py
+++ b/tests/unit/templating/test_media_types_finders.py
@@ -23,25 +23,25 @@ def finder(self, content):
         return MediaTypeFinder(content)
 
     def test_exact(self, finder, content):
-        response = MockResponse("", mimetype="application/json")
+        mimetype = "application/json"
 
-        _, mimetype = finder.find(response)
+        _, mimetype = finder.find(mimetype)
         assert mimetype == "application/json"
 
     def test_match(self, finder, content):
-        response = MockResponse("", mimetype="text/html")
+        mimetype = "text/html"
 
-        _, mimetype = finder.find(response)
+        _, mimetype = finder.find(mimetype)
         assert mimetype == "text/*"
 
     def test_not_found(self, finder, content):
-        response = MockResponse("", mimetype="unknown")
+        mimetype = "unknown"
 
         with pytest.raises(MediaTypeNotFound):
-            finder.find(response)
+            finder.find(mimetype)
 
     def test_missing(self, finder, content):
-        response = MockResponse("", mimetype=None)
+        mimetype = None
 
         with pytest.raises(MediaTypeNotFound):
-            finder.find(response)
+            finder.find(mimetype)