diff --git a/fastapi/_compat.py b/fastapi/_compat.py
index 33ad5d125..85a017fc0 100644
--- a/fastapi/_compat.py
+++ b/fastapi/_compat.py
@@ -47,8 +47,6 @@ if PYDANTIC_V2:
     from pydantic import PydanticSchemaGenerationError as PydanticSchemaGenerationError
     from pydantic import TypeAdapter
     from pydantic import ValidationError as ValidationError
-    from pydantic._internal._fields import Undefined as Undefined
-    from pydantic._internal._fields import _UndefinedType
     from pydantic._internal._schema_generation_shared import (  # type: ignore[attr-defined]
         GetJsonSchemaHandler as GetJsonSchemaHandler,
     )
@@ -58,15 +56,16 @@ if PYDANTIC_V2:
     from pydantic.json_schema import GenerateJsonSchema as GenerateJsonSchema
     from pydantic.json_schema import JsonSchemaValue as JsonSchemaValue
     from pydantic_core import CoreSchema as CoreSchema
-    from pydantic_core import ErrorDetails
     from pydantic_core import MultiHostUrl as MultiHostUrl
+    from pydantic_core import PydanticUndefined, PydanticUndefinedType
     from pydantic_core import Url as Url
     from pydantic_core.core_schema import (
         general_plain_validator_function as general_plain_validator_function,
     )
 
-    Required = Undefined
-    UndefinedType = _UndefinedType
+    Required = PydanticUndefined
+    Undefined = PydanticUndefined
+    UndefinedType = PydanticUndefinedType
     evaluate_forwardref = eval_type_lenient
     Validator = Any
 
@@ -303,7 +302,6 @@ else:
         lenient_issubclass as lenient_issubclass,  # noqa: F401
     )
 
-    ErrorDetails = Dict[str, Any]  # type: ignore[assignment,misc]
     GetJsonSchemaHandler = Any  # type: ignore[assignment,misc]
     JsonSchemaValue = Dict[str, Any]  # type: ignore[misc]
     CoreSchema = Any  # type: ignore[assignment,misc]
diff --git a/tests/test_path.py b/tests/test_path.py
index 83c12a7c7..848b245e2 100644
--- a/tests/test_path.py
+++ b/tests/test_path.py
@@ -145,7 +145,7 @@ def test_path_float_foobar():
                 {
                     "type": "float_parsing",
                     "loc": ["path", "item_id"],
-                    "msg": "Input should be a valid number, unable to parse string as an number",
+                    "msg": "Input should be a valid number, unable to parse string as a number",
                     "input": "foobar",
                     "url": match_pydantic_error_url("float_parsing"),
                 }
@@ -174,7 +174,7 @@ def test_path_float_True():
                 {
                     "type": "float_parsing",
                     "loc": ["path", "item_id"],
-                    "msg": "Input should be a valid number, unable to parse string as an number",
+                    "msg": "Input should be a valid number, unable to parse string as a number",
                     "input": "True",
                     "url": match_pydantic_error_url("float_parsing"),
                 }
diff --git a/tests/test_tutorial/test_body/test_tutorial001.py b/tests/test_tutorial/test_body/test_tutorial001.py
index 3a07f787d..690e97c24 100644
--- a/tests/test_tutorial/test_body/test_tutorial001.py
+++ b/tests/test_tutorial/test_body/test_tutorial001.py
@@ -101,7 +101,7 @@ def test_post_with_only_name_price(client: TestClient):
                 {
                     "type": "float_parsing",
                     "loc": ["body", "price"],
-                    "msg": "Input should be a valid number, unable to parse string as an number",
+                    "msg": "Input should be a valid number, unable to parse string as a number",
                     "input": "twenty",
                     "url": match_pydantic_error_url("float_parsing"),
                 }
@@ -240,11 +240,11 @@ def test_post_form_for_json(client: TestClient):
         {
             "detail": [
                 {
-                    "type": "dict_attributes_type",
+                    "type": "model_attributes_type",
                     "loc": ["body"],
-                    "msg": "Input should be a valid dictionary or instance to extract fields from",
+                    "msg": "Input should be a valid dictionary or object to extract fields from",
                     "input": "name=Foo&price=50.5",
-                    "url": match_pydantic_error_url("dict_attributes_type"),
+                    "url": match_pydantic_error_url("model_attributes_type"),
                 }
             ]
         }
@@ -304,12 +304,12 @@ def test_wrong_headers(client: TestClient):
         {
             "detail": [
                 {
-                    "type": "dict_attributes_type",
+                    "type": "model_attributes_type",
                     "loc": ["body"],
-                    "msg": "Input should be a valid dictionary or instance to extract fields from",
+                    "msg": "Input should be a valid dictionary or object to extract fields from",
                     "input": '{"name": "Foo", "price": 50.5}',
                     "url": match_pydantic_error_url(
-                        "dict_attributes_type"
+                        "model_attributes_type"
                     ),  # "https://errors.pydantic.dev/0.38.0/v/dict_attributes_type",
                 }
             ]
@@ -335,11 +335,11 @@ def test_wrong_headers(client: TestClient):
         {
             "detail": [
                 {
-                    "type": "dict_attributes_type",
+                    "type": "model_attributes_type",
                     "loc": ["body"],
-                    "msg": "Input should be a valid dictionary or instance to extract fields from",
+                    "msg": "Input should be a valid dictionary or object to extract fields from",
                     "input": '{"name": "Foo", "price": 50.5}',
-                    "url": match_pydantic_error_url("dict_attributes_type"),
+                    "url": match_pydantic_error_url("model_attributes_type"),
                 }
             ]
         }
@@ -363,11 +363,11 @@ def test_wrong_headers(client: TestClient):
         {
             "detail": [
                 {
-                    "type": "dict_attributes_type",
+                    "type": "model_attributes_type",
                     "loc": ["body"],
-                    "msg": "Input should be a valid dictionary or instance to extract fields from",
+                    "msg": "Input should be a valid dictionary or object to extract fields from",
                     "input": '{"name": "Foo", "price": 50.5}',
-                    "url": match_pydantic_error_url("dict_attributes_type"),
+                    "url": match_pydantic_error_url("model_attributes_type"),
                 }
             ]
         }
diff --git a/tests/test_tutorial/test_body/test_tutorial001_py310.py b/tests/test_tutorial/test_body/test_tutorial001_py310.py
index dd0207350..ac4b9bdbe 100644
--- a/tests/test_tutorial/test_body/test_tutorial001_py310.py
+++ b/tests/test_tutorial/test_body/test_tutorial001_py310.py
@@ -109,7 +109,7 @@ def test_post_with_only_name_price(client: TestClient):
                 {
                     "type": "float_parsing",
                     "loc": ["body", "price"],
-                    "msg": "Input should be a valid number, unable to parse string as an number",
+                    "msg": "Input should be a valid number, unable to parse string as a number",
                     "input": "twenty",
                     "url": match_pydantic_error_url("float_parsing"),
                 }
@@ -252,11 +252,11 @@ def test_post_form_for_json(client: TestClient):
         {
             "detail": [
                 {
-                    "type": "dict_attributes_type",
+                    "type": "model_attributes_type",
                     "loc": ["body"],
-                    "msg": "Input should be a valid dictionary or instance to extract fields from",
+                    "msg": "Input should be a valid dictionary or object to extract fields from",
                     "input": "name=Foo&price=50.5",
-                    "url": match_pydantic_error_url("dict_attributes_type"),
+                    "url": match_pydantic_error_url("model_attributes_type"),
                 }
             ]
         }
@@ -320,11 +320,11 @@ def test_wrong_headers(client: TestClient):
         {
             "detail": [
                 {
-                    "type": "dict_attributes_type",
+                    "type": "model_attributes_type",
                     "loc": ["body"],
-                    "msg": "Input should be a valid dictionary or instance to extract fields from",
+                    "msg": "Input should be a valid dictionary or object to extract fields from",
                     "input": '{"name": "Foo", "price": 50.5}',
-                    "url": match_pydantic_error_url("dict_attributes_type"),
+                    "url": match_pydantic_error_url("model_attributes_type"),
                 }
             ]
         }
@@ -349,11 +349,11 @@ def test_wrong_headers(client: TestClient):
         {
             "detail": [
                 {
-                    "type": "dict_attributes_type",
+                    "type": "model_attributes_type",
                     "loc": ["body"],
-                    "msg": "Input should be a valid dictionary or instance to extract fields from",
+                    "msg": "Input should be a valid dictionary or object to extract fields from",
                     "input": '{"name": "Foo", "price": 50.5}',
-                    "url": match_pydantic_error_url("dict_attributes_type"),
+                    "url": match_pydantic_error_url("model_attributes_type"),
                 }
             ]
         }
@@ -377,11 +377,11 @@ def test_wrong_headers(client: TestClient):
         {
             "detail": [
                 {
-                    "type": "dict_attributes_type",
+                    "type": "model_attributes_type",
                     "loc": ["body"],
-                    "msg": "Input should be a valid dictionary or instance to extract fields from",
+                    "msg": "Input should be a valid dictionary or object to extract fields from",
                     "input": '{"name": "Foo", "price": 50.5}',
-                    "url": match_pydantic_error_url("dict_attributes_type"),
+                    "url": match_pydantic_error_url("model_attributes_type"),
                 }
             ]
         }
diff --git a/tests/test_tutorial/test_dataclasses/test_tutorial001.py b/tests/test_tutorial/test_dataclasses/test_tutorial001.py
index 4a2d9f053..a325103bc 100644
--- a/tests/test_tutorial/test_dataclasses/test_tutorial001.py
+++ b/tests/test_tutorial/test_dataclasses/test_tutorial001.py
@@ -27,7 +27,7 @@ def test_post_invalid_item():
                 {
                     "type": "float_parsing",
                     "loc": ["body", "price"],
-                    "msg": "Input should be a valid number, unable to parse string as an number",
+                    "msg": "Input should be a valid number, unable to parse string as a number",
                     "input": "invalid price",
                     "url": match_pydantic_error_url("float_parsing"),
                 }