diff --git a/services/dcs/src/dcs/core/data_repository.py b/services/dcs/src/dcs/core/data_repository.py
index 3cceb97..4dc3573 100644
--- a/services/dcs/src/dcs/core/data_repository.py
+++ b/services/dcs/src/dcs/core/data_repository.py
@@ -28,7 +28,7 @@
     S3ObjectStoragesConfig,
 )
 from hexkit.protocols.objstorage import ObjectStorageProtocol
-from pydantic import Field, PositiveInt, field_validator
+from pydantic import Field, PositiveInt, field_validator, model_validator
 from pydantic_settings import BaseSettings
 
 from dcs.adapters.outbound.http import exceptions
@@ -56,21 +56,21 @@ class DataRepositoryConfig(BaseSettings):
         examples=["drs://localhost:8080/"],
     )
     staging_speed: int = Field(
-        100,
+        default=100,
         description="When trying to access a DRS object that is not yet in the outbox,"
         + " assume that this many megabytes can be staged per second.",
         title="Staging speed in MB/s",
         examples=[100, 500],
     )
     retry_after_min: int = Field(
-        5,
+        default=5,
         description="When trying to access a DRS object that is not yet in the outbox,"
         + " wait at least this number of seconds before trying again.",
         title="Minimum retry time in seconds when staging",
         examples=[5, 10],
     )
     retry_after_max: int = Field(
-        300,
+        default=300,
         description="When trying to access a DRS object that is not yet in the outbox,"
         + " wait at most this number of seconds before trying again.",
         title="Maximum retry time in seconds when staging",
@@ -98,7 +98,7 @@ class DataRepositoryConfig(BaseSettings):
         examples=[5, 10],
     )
     cache_timeout: int = Field(
-        7,
+        default=7,
         description="Time in days since last access after which a file present in the "
         + "outbox should be unstaged and has to be requested from permanent storage again "
         + "for the next request.",
@@ -118,6 +118,19 @@ def check_server_uri(cls, value: str):
 
         return value
 
+    @model_validator(mode="after")
+    def check_url_expiration_buffer(self):
+        """Check that the buffer is less than the expiration time."""
+        value = self.url_expiration_buffer
+        if value >= self.presigned_url_expires_after:
+            message = (
+                "url_expiration_buffer must be less than presigned_url_expires_after"
+                + f", got: {value} (should be less than"
+                + f" {self.presigned_url_expires_after})"
+            )
+            raise ValueError(message)
+        return self
+
 
 class DataRepository(DataRepositoryPort):
     """A service that manages a registry of DRS objects."""
diff --git a/services/dcs/tests_dcs/test_edge_cases.py b/services/dcs/tests_dcs/test_edge_cases.py
index eeee5cf..0f31e1b 100644
--- a/services/dcs/tests_dcs/test_edge_cases.py
+++ b/services/dcs/tests_dcs/test_edge_cases.py
@@ -29,6 +29,7 @@
 
 from dcs.config import Config
 from dcs.core import models
+from dcs.core.data_repository import DataRepositoryConfig
 from dcs.inject import prepare_rest_app
 from dcs.ports.outbound.dao import DrsObjectDaoPort
 from tests_dcs.fixtures.joint import EXAMPLE_FILE, JointFixture, PopulatedFixture
@@ -239,3 +240,21 @@ async def test_cache_headers(
 
         assert "Cache-Control" in response.headers
         assert response.headers["Cache-Control"] == f"max-age={expected_url_max_age}"
+
+
+async def test_cache_param_validation():
+    """Test that the http cache-related config parameters are validated correctly"""
+    with pytest.raises(ValueError):
+        DataRepositoryConfig(
+            drs_server_uri="",
+            ekss_base_url="",
+            presigned_url_expires_after=0,
+            url_expiration_buffer=10,
+        )
+    with pytest.raises(ValueError):
+        DataRepositoryConfig(
+            drs_server_uri="",
+            ekss_base_url="",
+            presigned_url_expires_after=10,
+            url_expiration_buffer=10,
+        )