diff --git a/ironic/drivers/modules/agent_base_vendor.py b/ironic/drivers/modules/agent_base_vendor.py
index f09aa4aff0..5f4478b9f0 100644
--- a/ironic/drivers/modules/agent_base_vendor.py
+++ b/ironic/drivers/modules/agent_base_vendor.py
@@ -318,7 +318,8 @@ class BaseAgentVendor(base.VendorInterface):
             # processing so the command hasn't started yet
             return
 
-        last_step = last_command['command_result'].get('clean_step')
+        last_result = last_command.get('command_result') or {}
+        last_step = last_result.get('clean_step')
         if last_command['command_status'] == 'RUNNING':
             return
         elif (last_command['command_status'] == 'SUCCEEDED' and
diff --git a/ironic/tests/drivers/test_agent_base_vendor.py b/ironic/tests/drivers/test_agent_base_vendor.py
index e672df85b7..851e124d59 100644
--- a/ironic/tests/drivers/test_agent_base_vendor.py
+++ b/ironic/tests/drivers/test_agent_base_vendor.py
@@ -513,7 +513,7 @@ class TestBaseAgentVendor(db_base.DbTestCase):
         status_mock.return_value = [{
             'command_status': 'RUNNING',
             'command_name': 'execute_clean_step',
-            'command_result': {}
+            'command_result': None
         }]
         with task_manager.acquire(self.context, self.node['uuid'],
                                   shared=False) as task: