diff --git a/airflow/api_fastapi/core_api/base.py b/airflow/api_fastapi/core_api/base.py
index fc1c68884c881..d88ec1757eb60 100644
--- a/airflow/api_fastapi/core_api/base.py
+++ b/airflow/api_fastapi/core_api/base.py
@@ -27,3 +27,15 @@ class BaseModel(PydanticBaseModel):
     """
 
     model_config = ConfigDict(from_attributes=True, populate_by_name=True)
+
+
+class StrictBaseModel(BaseModel):
+    """
+    StrictBaseModel is a base Pydantic model for REST API that does not allow any extra fields.
+
+    Use this class for models that should not have any extra fields in the payload.
+
+    :meta private:
+    """
+
+    model_config = ConfigDict(from_attributes=True, populate_by_name=True, extra="forbid")
diff --git a/airflow/api_fastapi/core_api/datamodels/assets.py b/airflow/api_fastapi/core_api/datamodels/assets.py
index c7b7bec034c06..fd8f7cef2d415 100644
--- a/airflow/api_fastapi/core_api/datamodels/assets.py
+++ b/airflow/api_fastapi/core_api/datamodels/assets.py
@@ -21,11 +21,11 @@
 
 from pydantic import Field, field_validator
 
-from airflow.api_fastapi.core_api.base import BaseModel
+from airflow.api_fastapi.core_api.base import BaseModel, StrictBaseModel
 from airflow.utils.log.secrets_masker import redact
 
 
-class DagScheduleAssetReference(BaseModel):
+class DagScheduleAssetReference(StrictBaseModel):
     """DAG schedule reference serializer for assets."""
 
     dag_id: str
@@ -33,7 +33,7 @@ class DagScheduleAssetReference(BaseModel):
     updated_at: datetime
 
 
-class TaskOutletAssetReference(BaseModel):
+class TaskOutletAssetReference(StrictBaseModel):
     """Task outlet reference serializer for assets."""
 
     dag_id: str
@@ -84,7 +84,7 @@ class AssetAliasCollectionResponse(BaseModel):
     total_entries: int
 
 
-class DagRunAssetReference(BaseModel):
+class DagRunAssetReference(StrictBaseModel):
     """DAGRun serializer for asset responses."""
 
     run_id: str
@@ -141,7 +141,7 @@ class QueuedEventCollectionResponse(BaseModel):
     total_entries: int
 
 
-class CreateAssetEventsBody(BaseModel):
+class CreateAssetEventsBody(StrictBaseModel):
     """Create asset events request."""
 
     asset_id: int
diff --git a/airflow/api_fastapi/core_api/datamodels/backfills.py b/airflow/api_fastapi/core_api/datamodels/backfills.py
index e36e50ea3b8d7..c74a7e2020313 100644
--- a/airflow/api_fastapi/core_api/datamodels/backfills.py
+++ b/airflow/api_fastapi/core_api/datamodels/backfills.py
@@ -19,11 +19,11 @@
 
 from datetime import datetime
 
-from airflow.api_fastapi.core_api.base import BaseModel
+from airflow.api_fastapi.core_api.base import BaseModel, StrictBaseModel
 from airflow.models.backfill import ReprocessBehavior
 
 
-class BackfillPostBody(BaseModel):
+class BackfillPostBody(StrictBaseModel):
     """Object used for create backfill request."""
 
     dag_id: str
diff --git a/airflow/api_fastapi/core_api/datamodels/common.py b/airflow/api_fastapi/core_api/datamodels/common.py
index 4af5356f2ed3a..3c7a04255c963 100644
--- a/airflow/api_fastapi/core_api/datamodels/common.py
+++ b/airflow/api_fastapi/core_api/datamodels/common.py
@@ -27,7 +27,7 @@
 
 from pydantic import Discriminator, Field, Tag
 
-from airflow.api_fastapi.core_api.base import BaseModel
+from airflow.api_fastapi.core_api.base import BaseModel, StrictBaseModel
 
 # Common Bulk Data Models
 T = TypeVar("T")
@@ -57,7 +57,7 @@ class BulkActionNotOnExistence(enum.Enum):
     SKIP = "skip"
 
 
-class BulkBaseAction(BaseModel, Generic[T]):
+class BulkBaseAction(StrictBaseModel, Generic[T]):
     """Base class for bulk actions."""
 
     action: BulkAction = Field(..., description="The action to be performed on the entities.")
@@ -88,7 +88,7 @@ def _action_discriminator(action: Any) -> str:
     return BulkAction(action["action"]).value
 
 
-class BulkBody(BaseModel, Generic[T]):
+class BulkBody(StrictBaseModel, Generic[T]):
     """Serializer for bulk entity operations."""
 
     actions: list[
diff --git a/airflow/api_fastapi/core_api/datamodels/config.py b/airflow/api_fastapi/core_api/datamodels/config.py
index c16aa98093fb1..42a327431ceed 100644
--- a/airflow/api_fastapi/core_api/datamodels/config.py
+++ b/airflow/api_fastapi/core_api/datamodels/config.py
@@ -16,10 +16,10 @@
 # under the License.
 from __future__ import annotations
 
-from airflow.api_fastapi.core_api.base import BaseModel
+from airflow.api_fastapi.core_api.base import StrictBaseModel
 
 
-class ConfigOption(BaseModel):
+class ConfigOption(StrictBaseModel):
     """Config option."""
 
     key: str
@@ -32,7 +32,7 @@ def text_format(self):
         return f"{self.key} = {self.value}"
 
 
-class ConfigSection(BaseModel):
+class ConfigSection(StrictBaseModel):
     """Config Section Schema."""
 
     name: str
@@ -53,7 +53,7 @@ def text_format(self):
         return f"[{self.name}]\n" + "\n".join(option.text_format for option in self.options) + "\n"
 
 
-class Config(BaseModel):
+class Config(StrictBaseModel):
     """List of config sections with their options."""
 
     sections: list[ConfigSection]
diff --git a/airflow/api_fastapi/core_api/datamodels/connections.py b/airflow/api_fastapi/core_api/datamodels/connections.py
index 00d075bc4ace4..4650e1354dc1e 100644
--- a/airflow/api_fastapi/core_api/datamodels/connections.py
+++ b/airflow/api_fastapi/core_api/datamodels/connections.py
@@ -22,7 +22,7 @@
 from pydantic import Field, field_validator
 from pydantic_core.core_schema import ValidationInfo
 
-from airflow.api_fastapi.core_api.base import BaseModel
+from airflow.api_fastapi.core_api.base import BaseModel, StrictBaseModel
 from airflow.utils.log.secrets_masker import redact
 
 
@@ -76,7 +76,7 @@ class ConnectionTestResponse(BaseModel):
 
 
 # Request Models
-class ConnectionBody(BaseModel):
+class ConnectionBody(StrictBaseModel):
     """Connection Serializer for requests body."""
 
     connection_id: str = Field(serialization_alias="conn_id", max_length=200, pattern=r"^[\w.-]+$")
diff --git a/airflow/api_fastapi/core_api/datamodels/dag_run.py b/airflow/api_fastapi/core_api/datamodels/dag_run.py
index 48c92d2a83cb0..78e0254f62240 100644
--- a/airflow/api_fastapi/core_api/datamodels/dag_run.py
+++ b/airflow/api_fastapi/core_api/datamodels/dag_run.py
@@ -22,7 +22,7 @@
 
 from pydantic import AwareDatetime, Field, NonNegativeInt, computed_field, model_validator
 
-from airflow.api_fastapi.core_api.base import BaseModel
+from airflow.api_fastapi.core_api.base import BaseModel, StrictBaseModel
 from airflow.models import DagRun
 from airflow.utils import timezone
 from airflow.utils.state import DagRunState
@@ -37,14 +37,14 @@ class DAGRunPatchStates(str, Enum):
     FAILED = DagRunState.FAILED
 
 
-class DAGRunPatchBody(BaseModel):
+class DAGRunPatchBody(StrictBaseModel):
     """DAG Run Serializer for PATCH requests."""
 
     state: DAGRunPatchStates | None = None
     note: str | None = Field(None, max_length=1000)
 
 
-class DAGRunClearBody(BaseModel):
+class DAGRunClearBody(StrictBaseModel):
     """DAG Run serializer for clear endpoint body."""
 
     dry_run: bool = True
@@ -78,7 +78,7 @@ class DAGRunCollectionResponse(BaseModel):
     total_entries: int
 
 
-class TriggerDAGRunPostBody(BaseModel):
+class TriggerDAGRunPostBody(StrictBaseModel):
     """Trigger DAG Run Serializer for POST body."""
 
     dag_run_id: str | None = None
@@ -109,7 +109,7 @@ def logical_date(self) -> datetime:
         return timezone.utcnow()
 
 
-class DAGRunsBatchBody(BaseModel):
+class DAGRunsBatchBody(StrictBaseModel):
     """List DAG Runs body for batch endpoint."""
 
     order_by: str | None = None
diff --git a/airflow/api_fastapi/core_api/datamodels/dags.py b/airflow/api_fastapi/core_api/datamodels/dags.py
index 30399b42f8d12..504a41683232c 100644
--- a/airflow/api_fastapi/core_api/datamodels/dags.py
+++ b/airflow/api_fastapi/core_api/datamodels/dags.py
@@ -31,7 +31,7 @@
     field_validator,
 )
 
-from airflow.api_fastapi.core_api.base import BaseModel
+from airflow.api_fastapi.core_api.base import BaseModel, StrictBaseModel
 from airflow.api_fastapi.core_api.datamodels.dag_tags import DagTagResponse
 from airflow.configuration import conf
 
@@ -92,7 +92,7 @@ def file_token(self) -> str:
         return serializer.dumps(self.fileloc)
 
 
-class DAGPatchBody(BaseModel):
+class DAGPatchBody(StrictBaseModel):
     """Dag Serializer for updatable bodies."""
 
     is_paused: bool
diff --git a/airflow/api_fastapi/core_api/datamodels/pools.py b/airflow/api_fastapi/core_api/datamodels/pools.py
index 0040c49a1efda..096e357dfaf1d 100644
--- a/airflow/api_fastapi/core_api/datamodels/pools.py
+++ b/airflow/api_fastapi/core_api/datamodels/pools.py
@@ -21,7 +21,7 @@
 
 from pydantic import BeforeValidator, ConfigDict, Field
 
-from airflow.api_fastapi.core_api.base import BaseModel
+from airflow.api_fastapi.core_api.base import BaseModel, StrictBaseModel
 
 
 def _call_function(function: Callable[[], int]) -> int:
@@ -60,7 +60,7 @@ class PoolCollectionResponse(BaseModel):
     total_entries: int
 
 
-class PoolPatchBody(BaseModel):
+class PoolPatchBody(StrictBaseModel):
     """Pool serializer for patch bodies."""
 
     model_config = ConfigDict(populate_by_name=True, from_attributes=True)
@@ -71,7 +71,7 @@ class PoolPatchBody(BaseModel):
     include_deferred: bool | None = None
 
 
-class PoolBody(BasePool):
+class PoolBody(BasePool, StrictBaseModel):
     """Pool serializer for post bodies."""
 
     pool: str = Field(alias="name", max_length=256)
diff --git a/airflow/api_fastapi/core_api/datamodels/task_instances.py b/airflow/api_fastapi/core_api/datamodels/task_instances.py
index 7cecb96ca42ce..d9c87b972ba9c 100644
--- a/airflow/api_fastapi/core_api/datamodels/task_instances.py
+++ b/airflow/api_fastapi/core_api/datamodels/task_instances.py
@@ -32,7 +32,7 @@
     model_validator,
 )
 
-from airflow.api_fastapi.core_api.base import BaseModel
+from airflow.api_fastapi.core_api.base import BaseModel, StrictBaseModel
 from airflow.api_fastapi.core_api.datamodels.job import JobResponse
 from airflow.api_fastapi.core_api.datamodels.trigger import TriggerResponse
 from airflow.utils.state import TaskInstanceState
@@ -97,7 +97,7 @@ class TaskDependencyCollectionResponse(BaseModel):
     dependencies: list[TaskDependencyResponse]
 
 
-class TaskInstancesBatchBody(BaseModel):
+class TaskInstancesBatchBody(StrictBaseModel):
     """Task Instance body for get batch."""
 
     dag_ids: list[str] | None = None
@@ -159,7 +159,7 @@ class TaskInstanceHistoryCollectionResponse(BaseModel):
     total_entries: int
 
 
-class ClearTaskInstancesBody(BaseModel):
+class ClearTaskInstancesBody(StrictBaseModel):
     """Request body for Clear Task Instances endpoint."""
 
     dry_run: bool = True
@@ -195,7 +195,7 @@ def validate_model(cls, data: Any) -> Any:
         return data
 
 
-class PatchTaskInstanceBody(BaseModel):
+class PatchTaskInstanceBody(StrictBaseModel):
     """Request body for Clear Task Instances endpoint."""
 
     new_state: TaskInstanceState | None = None
diff --git a/airflow/api_fastapi/core_api/datamodels/variables.py b/airflow/api_fastapi/core_api/datamodels/variables.py
index 8307809bc5f5b..82cfdbb130523 100644
--- a/airflow/api_fastapi/core_api/datamodels/variables.py
+++ b/airflow/api_fastapi/core_api/datamodels/variables.py
@@ -21,7 +21,7 @@
 
 from pydantic import ConfigDict, Field, model_validator
 
-from airflow.api_fastapi.core_api.base import BaseModel
+from airflow.api_fastapi.core_api.base import BaseModel, StrictBaseModel
 from airflow.models.base import ID_LEN
 from airflow.typing_compat import Self
 from airflow.utils.log.secrets_masker import redact
@@ -52,7 +52,7 @@ def redact_val(self) -> Self:
             return self
 
 
-class VariableBody(BaseModel):
+class VariableBody(StrictBaseModel):
     """Variable serializer for bodies."""
 
     key: str = Field(max_length=ID_LEN)
diff --git a/airflow/api_fastapi/core_api/datamodels/xcom.py b/airflow/api_fastapi/core_api/datamodels/xcom.py
index 3a819b317d760..b63db3ff87d15 100644
--- a/airflow/api_fastapi/core_api/datamodels/xcom.py
+++ b/airflow/api_fastapi/core_api/datamodels/xcom.py
@@ -52,8 +52,8 @@ def value_to_string(cls, v):
         return str(v) if v is not None else None
 
 
-class XComCollection(BaseModel):
-    """List of XCom items."""
+class XComCollectionResponse(BaseModel):
+    """XCom Collection serializer for responses."""
 
     xcom_entries: list[XComResponse]
     total_entries: int
diff --git a/airflow/api_fastapi/core_api/openapi/v1-generated.yaml b/airflow/api_fastapi/core_api/openapi/v1-generated.yaml
index 62df27b568ecd..4ffef0ab838cc 100644
--- a/airflow/api_fastapi/core_api/openapi/v1-generated.yaml
+++ b/airflow/api_fastapi/core_api/openapi/v1-generated.yaml
@@ -4426,7 +4426,7 @@ paths:
           content:
             application/json:
               schema:
-                $ref: '#/components/schemas/XComCollection'
+                $ref: '#/components/schemas/XComCollectionResponse'
         '401':
           content:
             application/json:
@@ -6785,6 +6785,7 @@ components:
           type: integer
           title: Max Active Runs
           default: 10
+      additionalProperties: false
       type: object
       required:
       - dag_id
@@ -6922,6 +6923,7 @@ components:
             - $ref: '#/components/schemas/BulkDeleteAction_ConnectionBody_'
           type: array
           title: Actions
+      additionalProperties: false
       type: object
       required:
       - actions
@@ -6936,6 +6938,7 @@ components:
             - $ref: '#/components/schemas/BulkDeleteAction_PoolBody_'
           type: array
           title: Actions
+      additionalProperties: false
       type: object
       required:
       - actions
@@ -6950,6 +6953,7 @@ components:
             - $ref: '#/components/schemas/BulkDeleteAction_VariableBody_'
           type: array
           title: Actions
+      additionalProperties: false
       type: object
       required:
       - actions
@@ -6968,6 +6972,7 @@ components:
         action_on_existence:
           $ref: '#/components/schemas/BulkActionOnExistence'
           default: fail
+      additionalProperties: false
       type: object
       required:
       - action
@@ -6987,6 +6992,7 @@ components:
         action_on_existence:
           $ref: '#/components/schemas/BulkActionOnExistence'
           default: fail
+      additionalProperties: false
       type: object
       required:
       - action
@@ -7006,6 +7012,7 @@ components:
         action_on_existence:
           $ref: '#/components/schemas/BulkActionOnExistence'
           default: fail
+      additionalProperties: false
       type: object
       required:
       - action
@@ -7025,6 +7032,7 @@ components:
         action_on_non_existence:
           $ref: '#/components/schemas/BulkActionNotOnExistence'
           default: fail
+      additionalProperties: false
       type: object
       required:
       - action
@@ -7044,6 +7052,7 @@ components:
         action_on_non_existence:
           $ref: '#/components/schemas/BulkActionNotOnExistence'
           default: fail
+      additionalProperties: false
       type: object
       required:
       - action
@@ -7063,6 +7072,7 @@ components:
         action_on_non_existence:
           $ref: '#/components/schemas/BulkActionNotOnExistence'
           default: fail
+      additionalProperties: false
       type: object
       required:
       - action
@@ -7115,6 +7125,7 @@ components:
         action_on_non_existence:
           $ref: '#/components/schemas/BulkActionNotOnExistence'
           default: fail
+      additionalProperties: false
       type: object
       required:
       - action
@@ -7134,6 +7145,7 @@ components:
         action_on_non_existence:
           $ref: '#/components/schemas/BulkActionNotOnExistence'
           default: fail
+      additionalProperties: false
       type: object
       required:
       - action
@@ -7153,6 +7165,7 @@ components:
         action_on_non_existence:
           $ref: '#/components/schemas/BulkActionNotOnExistence'
           default: fail
+      additionalProperties: false
       type: object
       required:
       - action
@@ -7223,6 +7236,7 @@ components:
           type: boolean
           title: Include Past
           default: false
+      additionalProperties: false
       type: object
       title: ClearTaskInstancesBody
       description: Request body for Clear Task Instances endpoint.
@@ -7233,6 +7247,7 @@ components:
             $ref: '#/components/schemas/ConfigSection'
           type: array
           title: Sections
+      additionalProperties: false
       type: object
       required:
       - sections
@@ -7253,6 +7268,7 @@ components:
             maxItems: 2
             minItems: 2
           title: Value
+      additionalProperties: false
       type: object
       required:
       - key
@@ -7355,6 +7371,7 @@ components:
             $ref: '#/components/schemas/ConfigOption'
           type: array
           title: Options
+      additionalProperties: false
       type: object
       required:
       - name
@@ -7406,6 +7423,7 @@ components:
           - type: string
           - type: 'null'
           title: Extra
+      additionalProperties: false
       type: object
       required:
       - connection_id
@@ -7745,6 +7763,7 @@ components:
         is_paused:
           type: boolean
           title: Is Paused
+      additionalProperties: false
       type: object
       required:
       - is_paused
@@ -7892,6 +7911,7 @@ components:
           type: boolean
           title: Only Failed
           default: false
+      additionalProperties: false
       type: object
       title: DAGRunClearBody
       description: DAG Run serializer for clear endpoint body.
@@ -7923,6 +7943,7 @@ components:
             maxLength: 1000
           - type: 'null'
           title: Note
+      additionalProperties: false
       type: object
       title: DAGRunPatchBody
       description: DAG Run Serializer for PATCH requests.
@@ -8133,6 +8154,7 @@ components:
             format: date-time
           - type: 'null'
           title: End Date Lte
+      additionalProperties: false
       type: object
       title: DAGRunsBatchBody
       description: List DAG Runs body for batch endpoint.
@@ -8417,6 +8439,7 @@ components:
           type: string
           format: date-time
           title: Data Interval End
+      additionalProperties: false
       type: object
       required:
       - run_id
@@ -8480,6 +8503,7 @@ components:
           type: string
           format: date-time
           title: Updated At
+      additionalProperties: false
       type: object
       required:
       - dag_id
@@ -9140,6 +9164,7 @@ components:
           type: boolean
           title: Include Past
           default: false
+      additionalProperties: false
       type: object
       title: PatchTaskInstanceBody
       description: Request body for Clear Task Instances endpoint.
@@ -9245,6 +9270,7 @@ components:
           type: boolean
           title: Include Deferred
           default: false
+      additionalProperties: false
       type: object
       required:
       - name
@@ -9289,6 +9315,7 @@ components:
           - type: boolean
           - type: 'null'
           title: Include Deferred
+      additionalProperties: false
       type: object
       title: PoolPatchBody
       description: Pool serializer for patch bodies.
@@ -10006,6 +10033,7 @@ components:
           - type: string
           - type: 'null'
           title: Order By
+      additionalProperties: false
       type: object
       title: TaskInstancesBatchBody
       description: Task Instance body for get batch.
@@ -10041,6 +10069,7 @@ components:
           type: string
           format: date-time
           title: Updated At
+      additionalProperties: false
       type: object
       required:
       - dag_id
@@ -10266,6 +10295,7 @@ components:
           - type: string
           - type: 'null'
           title: Note
+      additionalProperties: false
       type: object
       title: TriggerDAGRunPostBody
       description: Trigger DAG Run Serializer for POST body.
@@ -10351,6 +10381,7 @@ components:
           - type: string
           - type: 'null'
           title: Description
+      additionalProperties: false
       type: object
       required:
       - key
@@ -10413,7 +10444,7 @@ components:
       - git_version
       title: VersionInfo
       description: Version information serializer for responses.
-    XComCollection:
+    XComCollectionResponse:
       properties:
         xcom_entries:
           items:
@@ -10427,8 +10458,8 @@ components:
       required:
       - xcom_entries
       - total_entries
-      title: XComCollection
-      description: List of XCom items.
+      title: XComCollectionResponse
+      description: XCom Collection serializer for responses.
     XComResponse:
       properties:
         key:
diff --git a/airflow/api_fastapi/core_api/routes/public/xcom.py b/airflow/api_fastapi/core_api/routes/public/xcom.py
index 524d0722d1caa..b8fa6456e570d 100644
--- a/airflow/api_fastapi/core_api/routes/public/xcom.py
+++ b/airflow/api_fastapi/core_api/routes/public/xcom.py
@@ -26,7 +26,7 @@
 from airflow.api_fastapi.common.parameters import QueryLimit, QueryOffset
 from airflow.api_fastapi.common.router import AirflowRouter
 from airflow.api_fastapi.core_api.datamodels.xcom import (
-    XComCollection,
+    XComCollectionResponse,
     XComResponseNative,
     XComResponseString,
 )
@@ -112,7 +112,7 @@ def get_xcom_entries(
     session: SessionDep,
     xcom_key: Annotated[str | None, Query()] = None,
     map_index: Annotated[int | None, Query(ge=-1)] = None,
-) -> XComCollection:
+) -> XComCollectionResponse:
     """
     Get all XCom entries.
 
@@ -140,4 +140,4 @@ def get_xcom_entries(
     )
     query = query.order_by(XCom.dag_id, XCom.task_id, XCom.run_id, XCom.map_index, XCom.key)
     xcoms = session.scalars(query)
-    return XComCollection(xcom_entries=xcoms, total_entries=total_entries)
+    return XComCollectionResponse(xcom_entries=xcoms, total_entries=total_entries)
diff --git a/airflow/api_fastapi/execution_api/datamodels/taskinstance.py b/airflow/api_fastapi/execution_api/datamodels/taskinstance.py
index 6cc82259cf758..abb2f6fa23c0a 100644
--- a/airflow/api_fastapi/execution_api/datamodels/taskinstance.py
+++ b/airflow/api_fastapi/execution_api/datamodels/taskinstance.py
@@ -32,7 +32,7 @@
 )
 
 from airflow.api_fastapi.common.types import UtcDateTime
-from airflow.api_fastapi.core_api.base import BaseModel
+from airflow.api_fastapi.core_api.base import BaseModel, StrictBaseModel
 from airflow.api_fastapi.execution_api.datamodels.asset import AssetProfile
 from airflow.api_fastapi.execution_api.datamodels.connection import ConnectionResponse
 from airflow.api_fastapi.execution_api.datamodels.variable import VariableResponse
@@ -42,7 +42,7 @@
 AwareDatetimeAdapter = TypeAdapter(AwareDatetime)
 
 
-class TIEnterRunningPayload(BaseModel):
+class TIEnterRunningPayload(StrictBaseModel):
     """Schema for updating TaskInstance to 'RUNNING' state with minimal required fields."""
 
     state: Annotated[
@@ -60,7 +60,7 @@ class TIEnterRunningPayload(BaseModel):
     """When the task started executing"""
 
 
-class TITerminalStatePayload(BaseModel):
+class TITerminalStatePayload(StrictBaseModel):
     """Schema for updating TaskInstance to a terminal state except SUCCESS state."""
 
     state: Literal[
@@ -74,7 +74,7 @@ class TITerminalStatePayload(BaseModel):
     """When the task completed executing"""
 
 
-class TISuccessStatePayload(BaseModel):
+class TISuccessStatePayload(StrictBaseModel):
     """Schema for updating TaskInstance to success state."""
 
     state: Annotated[
@@ -96,13 +96,13 @@ class TISuccessStatePayload(BaseModel):
     outlet_events: Annotated[list[Any], Field(default_factory=list)]
 
 
-class TITargetStatePayload(BaseModel):
+class TITargetStatePayload(StrictBaseModel):
     """Schema for updating TaskInstance to a target state, excluding terminal and running states."""
 
     state: IntermediateTIState
 
 
-class TIDeferredStatePayload(BaseModel):
+class TIDeferredStatePayload(StrictBaseModel):
     """Schema for updating TaskInstance to a deferred state."""
 
     state: Annotated[
@@ -128,7 +128,7 @@ def validate_moment(cls, v):
         return v
 
 
-class TIRescheduleStatePayload(BaseModel):
+class TIRescheduleStatePayload(StrictBaseModel):
     """Schema for updating TaskInstance to a up_for_reschedule state."""
 
     state: Annotated[
@@ -146,7 +146,7 @@ class TIRescheduleStatePayload(BaseModel):
     end_date: UtcDateTime
 
 
-def ti_state_discriminator(v: dict[str, str] | BaseModel) -> str:
+def ti_state_discriminator(v: dict[str, str] | StrictBaseModel) -> str:
     """
     Determine the discriminator key for TaskInstance state transitions.
 
@@ -185,7 +185,7 @@ def ti_state_discriminator(v: dict[str, str] | BaseModel) -> str:
 ]
 
 
-class TIHeartbeatInfo(BaseModel):
+class TIHeartbeatInfo(StrictBaseModel):
     """Schema for TaskInstance heartbeat endpoint."""
 
     hostname: str
@@ -194,7 +194,7 @@ class TIHeartbeatInfo(BaseModel):
 
 # This model is not used in the API, but it is included in generated OpenAPI schema
 # for use in the client SDKs.
-class TaskInstance(BaseModel):
+class TaskInstance(StrictBaseModel):
     """Schema for TaskInstance model with minimal required fields needed for Runtime."""
 
     id: uuid.UUID
@@ -207,7 +207,7 @@ class TaskInstance(BaseModel):
     hostname: str | None = None
 
 
-class DagRun(BaseModel):
+class DagRun(StrictBaseModel):
     """Schema for DagRun model with minimal required fields needed for Runtime."""
 
     # TODO: `dag_id` and `run_id` are duplicated from TaskInstance
diff --git a/airflow/api_fastapi/execution_api/datamodels/variable.py b/airflow/api_fastapi/execution_api/datamodels/variable.py
index 6c597524763aa..73361908a810f 100644
--- a/airflow/api_fastapi/execution_api/datamodels/variable.py
+++ b/airflow/api_fastapi/execution_api/datamodels/variable.py
@@ -19,7 +19,7 @@
 
 from pydantic import Field
 
-from airflow.api_fastapi.core_api.base import BaseModel, ConfigDict
+from airflow.api_fastapi.core_api.base import BaseModel, ConfigDict, StrictBaseModel
 
 
 class VariableResponse(BaseModel):
@@ -29,7 +29,7 @@ class VariableResponse(BaseModel):
     val: str | None = Field(alias="value")
 
 
-class VariablePostBody(BaseModel):
+class VariablePostBody(StrictBaseModel):
     """Request body schema for creating variables."""
 
     model_config = ConfigDict(extra="forbid")
diff --git a/airflow/auth/managers/simple/datamodels/login.py b/airflow/auth/managers/simple/datamodels/login.py
index 9d8eef55d23ba..ff4883625eccd 100644
--- a/airflow/auth/managers/simple/datamodels/login.py
+++ b/airflow/auth/managers/simple/datamodels/login.py
@@ -19,7 +19,7 @@
 
 from pydantic import Field
 
-from airflow.api_fastapi.core_api.base import BaseModel
+from airflow.api_fastapi.core_api.base import BaseModel, StrictBaseModel
 
 
 class LoginResponse(BaseModel):
@@ -28,7 +28,7 @@ class LoginResponse(BaseModel):
     jwt_token: str
 
 
-class LoginBody(BaseModel):
+class LoginBody(StrictBaseModel):
     """Login serializer for post bodies."""
 
     username: str = Field()
diff --git a/airflow/auth/managers/simple/openapi/v1-generated.yaml b/airflow/auth/managers/simple/openapi/v1-generated.yaml
index 4ae5c70876149..d0efc68864d17 100644
--- a/airflow/auth/managers/simple/openapi/v1-generated.yaml
+++ b/airflow/auth/managers/simple/openapi/v1-generated.yaml
@@ -75,6 +75,7 @@ components:
         password:
           type: string
           title: Password
+      additionalProperties: false
       type: object
       required:
       - username
diff --git a/airflow/ui/openapi-gen/queries/prefetch.ts b/airflow/ui/openapi-gen/queries/prefetch.ts
index 63a949aca94e6..b40c3243b0ded 100644
--- a/airflow/ui/openapi-gen/queries/prefetch.ts
+++ b/airflow/ui/openapi-gen/queries/prefetch.ts
@@ -2123,7 +2123,7 @@ export const prefetchUseXcomServiceGetXcomEntry = (
  * @param data.mapIndex
  * @param data.limit
  * @param data.offset
- * @returns XComCollection Successful Response
+ * @returns XComCollectionResponse Successful Response
  * @throws ApiError
  */
 export const prefetchUseXcomServiceGetXcomEntries = (
diff --git a/airflow/ui/openapi-gen/queries/queries.ts b/airflow/ui/openapi-gen/queries/queries.ts
index c4d201767e17d..04905e188e495 100644
--- a/airflow/ui/openapi-gen/queries/queries.ts
+++ b/airflow/ui/openapi-gen/queries/queries.ts
@@ -2503,7 +2503,7 @@ export const useXcomServiceGetXcomEntry = <
  * @param data.mapIndex
  * @param data.limit
  * @param data.offset
- * @returns XComCollection Successful Response
+ * @returns XComCollectionResponse Successful Response
  * @throws ApiError
  */
 export const useXcomServiceGetXcomEntries = <
diff --git a/airflow/ui/openapi-gen/queries/suspense.ts b/airflow/ui/openapi-gen/queries/suspense.ts
index d2f3bfc937c72..63beafe117da2 100644
--- a/airflow/ui/openapi-gen/queries/suspense.ts
+++ b/airflow/ui/openapi-gen/queries/suspense.ts
@@ -2482,7 +2482,7 @@ export const useXcomServiceGetXcomEntrySuspense = <
  * @param data.mapIndex
  * @param data.limit
  * @param data.offset
- * @returns XComCollection Successful Response
+ * @returns XComCollectionResponse Successful Response
  * @throws ApiError
  */
 export const useXcomServiceGetXcomEntriesSuspense = <
diff --git a/airflow/ui/openapi-gen/requests/schemas.gen.ts b/airflow/ui/openapi-gen/requests/schemas.gen.ts
index 170b977beb0ed..8b30ecc9c1ec0 100644
--- a/airflow/ui/openapi-gen/requests/schemas.gen.ts
+++ b/airflow/ui/openapi-gen/requests/schemas.gen.ts
@@ -413,6 +413,7 @@ export const $BackfillPostBody = {
       default: 10,
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["dag_id", "from_date", "to_date"],
   title: "BackfillPostBody",
@@ -587,6 +588,7 @@ export const $BulkBody_ConnectionBody_ = {
       title: "Actions",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["actions"],
   title: "BulkBody[ConnectionBody]",
@@ -612,6 +614,7 @@ export const $BulkBody_PoolBody_ = {
       title: "Actions",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["actions"],
   title: "BulkBody[PoolBody]",
@@ -637,6 +640,7 @@ export const $BulkBody_VariableBody_ = {
       title: "Actions",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["actions"],
   title: "BulkBody[VariableBody]",
@@ -661,6 +665,7 @@ export const $BulkCreateAction_ConnectionBody_ = {
       default: "fail",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["action", "entities"],
   title: "BulkCreateAction[ConnectionBody]",
@@ -685,6 +690,7 @@ export const $BulkCreateAction_PoolBody_ = {
       default: "fail",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["action", "entities"],
   title: "BulkCreateAction[PoolBody]",
@@ -709,6 +715,7 @@ export const $BulkCreateAction_VariableBody_ = {
       default: "fail",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["action", "entities"],
   title: "BulkCreateAction[VariableBody]",
@@ -733,6 +740,7 @@ export const $BulkDeleteAction_ConnectionBody_ = {
       default: "fail",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["action", "entities"],
   title: "BulkDeleteAction[ConnectionBody]",
@@ -757,6 +765,7 @@ export const $BulkDeleteAction_PoolBody_ = {
       default: "fail",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["action", "entities"],
   title: "BulkDeleteAction[PoolBody]",
@@ -781,6 +790,7 @@ export const $BulkDeleteAction_VariableBody_ = {
       default: "fail",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["action", "entities"],
   title: "BulkDeleteAction[VariableBody]",
@@ -850,6 +860,7 @@ export const $BulkUpdateAction_ConnectionBody_ = {
       default: "fail",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["action", "entities"],
   title: "BulkUpdateAction[ConnectionBody]",
@@ -874,6 +885,7 @@ export const $BulkUpdateAction_PoolBody_ = {
       default: "fail",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["action", "entities"],
   title: "BulkUpdateAction[PoolBody]",
@@ -898,6 +910,7 @@ export const $BulkUpdateAction_VariableBody_ = {
       default: "fail",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["action", "entities"],
   title: "BulkUpdateAction[VariableBody]",
@@ -1012,6 +1025,7 @@ export const $ClearTaskInstancesBody = {
       default: false,
     },
   },
+  additionalProperties: false,
   type: "object",
   title: "ClearTaskInstancesBody",
   description: "Request body for Clear Task Instances endpoint.",
@@ -1027,6 +1041,7 @@ export const $Config = {
       title: "Sections",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["sections"],
   title: "Config",
@@ -1061,6 +1076,7 @@ export const $ConfigOption = {
       title: "Value",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["key", "value"],
   title: "ConfigOption",
@@ -1191,6 +1207,7 @@ export const $ConfigSection = {
       title: "Options",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["name", "options"],
   title: "ConfigSection",
@@ -1287,6 +1304,7 @@ export const $ConnectionBody = {
       title: "Extra",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["connection_id", "conn_type"],
   title: "ConnectionBody",
@@ -1839,6 +1857,7 @@ export const $DAGPatchBody = {
       title: "Is Paused",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["is_paused"],
   title: "DAGPatchBody",
@@ -2074,6 +2093,7 @@ export const $DAGRunClearBody = {
       default: false,
     },
   },
+  additionalProperties: false,
   type: "object",
   title: "DAGRunClearBody",
   description: "DAG Run serializer for clear endpoint body.",
@@ -2124,6 +2144,7 @@ export const $DAGRunPatchBody = {
       title: "Note",
     },
   },
+  additionalProperties: false,
   type: "object",
   title: "DAGRunPatchBody",
   description: "DAG Run Serializer for PATCH requests.",
@@ -2464,6 +2485,7 @@ export const $DAGRunsBatchBody = {
       title: "End Date Lte",
     },
   },
+  additionalProperties: false,
   type: "object",
   title: "DAGRunsBatchBody",
   description: "List DAG Runs body for batch endpoint.",
@@ -2891,6 +2913,7 @@ export const $DagRunAssetReference = {
       title: "Data Interval End",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: [
     "run_id",
@@ -2948,6 +2971,7 @@ export const $DagScheduleAssetReference = {
       title: "Updated At",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["dag_id", "created_at", "updated_at"],
   title: "DagScheduleAssetReference",
@@ -3956,6 +3980,7 @@ export const $PatchTaskInstanceBody = {
       default: false,
     },
   },
+  additionalProperties: false,
   type: "object",
   title: "PatchTaskInstanceBody",
   description: "Request body for Clear Task Instances endpoint.",
@@ -4101,6 +4126,7 @@ export const $PoolBody = {
       default: false,
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["name", "slots"],
   title: "PoolBody",
@@ -4174,6 +4200,7 @@ export const $PoolPatchBody = {
       title: "Include Deferred",
     },
   },
+  additionalProperties: false,
   type: "object",
   title: "PoolPatchBody",
   description: "Pool serializer for patch bodies.",
@@ -5286,6 +5313,7 @@ export const $TaskInstancesBatchBody = {
       title: "Order By",
     },
   },
+  additionalProperties: false,
   type: "object",
   title: "TaskInstancesBatchBody",
   description: "Task Instance body for get batch.",
@@ -5336,6 +5364,7 @@ export const $TaskOutletAssetReference = {
       title: "Updated At",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["dag_id", "task_id", "created_at", "updated_at"],
   title: "TaskOutletAssetReference",
@@ -5738,6 +5767,7 @@ export const $TriggerDAGRunPostBody = {
       title: "Note",
     },
   },
+  additionalProperties: false,
   type: "object",
   title: "TriggerDAGRunPostBody",
   description: "Trigger DAG Run Serializer for POST body.",
@@ -5864,6 +5894,7 @@ export const $VariableBody = {
       title: "Description",
     },
   },
+  additionalProperties: false,
   type: "object",
   required: ["key", "value"],
   title: "VariableBody",
@@ -5946,7 +5977,7 @@ export const $VersionInfo = {
   description: "Version information serializer for responses.",
 } as const;
 
-export const $XComCollection = {
+export const $XComCollectionResponse = {
   properties: {
     xcom_entries: {
       items: {
@@ -5962,8 +5993,8 @@ export const $XComCollection = {
   },
   type: "object",
   required: ["xcom_entries", "total_entries"],
-  title: "XComCollection",
-  description: "List of XCom items.",
+  title: "XComCollectionResponse",
+  description: "XCom Collection serializer for responses.",
 } as const;
 
 export const $XComResponse = {
diff --git a/airflow/ui/openapi-gen/requests/services.gen.ts b/airflow/ui/openapi-gen/requests/services.gen.ts
index bf6e528da11ed..0e3c33dba9d65 100644
--- a/airflow/ui/openapi-gen/requests/services.gen.ts
+++ b/airflow/ui/openapi-gen/requests/services.gen.ts
@@ -2978,7 +2978,7 @@ export class XcomService {
    * @param data.mapIndex
    * @param data.limit
    * @param data.offset
-   * @returns XComCollection Successful Response
+   * @returns XComCollectionResponse Successful Response
    * @throws ApiError
    */
   public static getXcomEntries(data: GetXcomEntriesData): CancelablePromise<GetXcomEntriesResponse> {
diff --git a/airflow/ui/openapi-gen/requests/types.gen.ts b/airflow/ui/openapi-gen/requests/types.gen.ts
index 6ff1a083ec6e8..3db3e1ea2ecf1 100644
--- a/airflow/ui/openapi-gen/requests/types.gen.ts
+++ b/airflow/ui/openapi-gen/requests/types.gen.ts
@@ -1469,9 +1469,9 @@ export type VersionInfo = {
 };
 
 /**
- * List of XCom items.
+ * XCom Collection serializer for responses.
  */
-export type XComCollection = {
+export type XComCollectionResponse = {
   xcom_entries: Array<XComResponse>;
   total_entries: number;
 };
@@ -2300,7 +2300,7 @@ export type GetXcomEntriesData = {
   xcomKey?: string | null;
 };
 
-export type GetXcomEntriesResponse = XComCollection;
+export type GetXcomEntriesResponse = XComCollectionResponse;
 
 export type GetTasksData = {
   dagId: string;
@@ -4698,7 +4698,7 @@ export type $OpenApiTs = {
         /**
          * Successful Response
          */
-        200: XComCollection;
+        200: XComCollectionResponse;
         /**
          * Bad Request
          */
diff --git a/tests/api_fastapi/core_api/routes/public/test_backfills.py b/tests/api_fastapi/core_api/routes/public/test_backfills.py
index 1836bae3ac7a1..1eeae8b667566 100644
--- a/tests/api_fastapi/core_api/routes/public/test_backfills.py
+++ b/tests/api_fastapi/core_api/routes/public/test_backfills.py
@@ -425,7 +425,6 @@ def test_create_backfill_dry_run_with_depends_on_past(
             "max_active_runs": max_active_runs,
             "run_backwards": run_backwards,
             "dag_run_conf": {"param1": "val1", "param2": True},
-            "dry_run": False,
             "reprocess_behavior": repro_act,
         }
         response = test_client.post(