diff --git a/swh/objstorage/tests/test_objstorage_azure.py b/swh/objstorage/tests/test_objstorage_azure.py
--- a/swh/objstorage/tests/test_objstorage_azure.py
+++ b/swh/objstorage/tests/test_objstorage_azure.py
@@ -14,6 +14,7 @@
 
 from swh.objstorage import get_objstorage
 from swh.objstorage.objstorage import decompressors
+from swh.objstorage.exc import Error
 
 from .objstorage_testing import ObjStorageTestFixture
 
@@ -99,6 +100,23 @@
         assert d.decompress(raw_blob.content) == content
         assert d.unused_data == b''
 
+    def test_trailing_data_on_stored_blob(self):
+        content, obj_id = self.hash_content(b'test content without garbage')
+        self.storage.add(content, obj_id=obj_id)
+
+        blob_service, container = self.storage.get_blob_service(obj_id)
+        internal_id = self.storage._internal_id(obj_id)
+
+        blob_service._data[container][internal_id] += b'trailing garbage'
+
+        if self.compression is not None:
+            with self.assertRaises(Error) as e:
+                self.storage.get(obj_id)
+            assert 'trailing data' in e.exception.args[0]
+        else:
+            with self.assertRaises(Error) as e:
+                self.storage.check(obj_id)
+
 
 class TestAzureCloudObjStorageGzip(TestAzureCloudObjStorage):
     compression = 'gzip'
diff --git a/swh/objstorage/tests/test_objstorage_cloud.py b/swh/objstorage/tests/test_objstorage_cloud.py
--- a/swh/objstorage/tests/test_objstorage_cloud.py
+++ b/swh/objstorage/tests/test_objstorage_cloud.py
@@ -13,6 +13,7 @@
 from swh.model import hashutil
 
 from swh.objstorage.objstorage import decompressors
+from swh.objstorage.exc import Error
 from swh.objstorage.backends.libcloud import CloudObjStorage
 
 from .objstorage_testing import ObjStorageTestFixture
@@ -115,6 +116,23 @@
         assert d.decompress(raw_content) == content
         assert d.unused_data == b''
 
+    def test_trailing_data_on_stored_blob(self):
+        content, obj_id = self.hash_content(b'test content without garbage')
+        self.storage.add(content, obj_id=obj_id)
+
+        data = self.storage.driver.containers[CONTAINER_NAME]
+        obj_id = hashutil.hash_to_hex(obj_id)
+
+        data[obj_id].content.append(b'trailing garbage')
+
+        if self.compression is not None:
+            with self.assertRaises(Error) as e:
+                self.storage.get(obj_id)
+            assert 'trailing data' in e.exception.args[0]
+        else:
+            with self.assertRaises(Error) as e:
+                self.storage.check(obj_id)
+
 
 class TestCloudObjStorageBz2(TestCloudObjStorage):
     compression = 'bz2'
diff --git a/swh/objstorage/tests/test_objstorage_seaweedfs.py b/swh/objstorage/tests/test_objstorage_seaweedfs.py
--- a/swh/objstorage/tests/test_objstorage_seaweedfs.py
+++ b/swh/objstorage/tests/test_objstorage_seaweedfs.py
@@ -8,6 +8,7 @@
 from typing import Optional
 
 from swh.objstorage.objstorage import decompressors
+from swh.objstorage.exc import Error
 
 from swh.objstorage.backends.seaweed import WeedObjStorage, DEFAULT_LIMIT
 from swh.objstorage.tests.objstorage_testing import ObjStorageTestFixture
@@ -60,6 +61,21 @@
         assert d.decompress(raw_content) == content
         assert d.unused_data == b''
 
+    def test_trailing_data_on_stored_blob(self):
+        content, obj_id = self.hash_content(b'test content without garbage')
+        self.storage.add(content, obj_id=obj_id)
+
+        path = self.storage._path(obj_id)
+        self.storage.wf.content[path] += b'trailing garbage'
+
+        if self.compression is not None:
+            with self.assertRaises(Error) as e:
+                self.storage.get(obj_id)
+            assert 'trailing data' in e.exception.args[0]
+        else:
+            with self.assertRaises(Error) as e:
+                self.storage.check(obj_id)
+
 
 class TestWeedObjStorageBz2(TestWeedObjStorage):
     compression = 'bz2'