diff --git a/homeassistant/components/deconz/deconz_event.py b/homeassistant/components/deconz/deconz_event.py
index 872dc3688c2..c5336825878 100644
--- a/homeassistant/components/deconz/deconz_event.py
+++ b/homeassistant/components/deconz/deconz_event.py
@@ -163,11 +163,13 @@ class DeconzAlarmEvent(DeconzEvent):
         if (
             self.gateway.ignore_state_updates
             or "action" not in self._device.changed_keys
-            or self._device.action == ""
         ):
             return
 
-        state, code, _area = self._device.action.split(",")
+        try:
+            state, code, _area = self._device.action.split(",")
+        except (AttributeError, ValueError):
+            return
 
         if state not in DECONZ_TO_ALARM_STATE:
             return
diff --git a/tests/components/deconz/test_deconz_event.py b/tests/components/deconz/test_deconz_event.py
index 798a96a43d7..418545f11cf 100644
--- a/tests/components/deconz/test_deconz_event.py
+++ b/tests/components/deconz/test_deconz_event.py
@@ -267,6 +267,50 @@ async def test_deconz_alarm_events(hass, aioclient_mock, mock_deconz_websocket):
 
     # Unsupported events
 
+    # Bad action string; string is None
+
+    event_changed_sensor = {
+        "t": "event",
+        "e": "changed",
+        "r": "sensors",
+        "id": "1",
+        "state": {"action": None},
+    }
+    await mock_deconz_websocket(data=event_changed_sensor)
+    await hass.async_block_till_done()
+
+    assert len(captured_events) == 1
+
+    # Bad action string; empty string
+
+    event_changed_sensor = {
+        "t": "event",
+        "e": "changed",
+        "r": "sensors",
+        "id": "1",
+        "state": {"action": ""},
+    }
+    await mock_deconz_websocket(data=event_changed_sensor)
+    await hass.async_block_till_done()
+
+    assert len(captured_events) == 1
+
+    # Bad action string; too few ","
+
+    event_changed_sensor = {
+        "t": "event",
+        "e": "changed",
+        "r": "sensors",
+        "id": "1",
+        "state": {"action": "armed_away,1234"},
+    }
+    await mock_deconz_websocket(data=event_changed_sensor)
+    await hass.async_block_till_done()
+
+    assert len(captured_events) == 1
+
+    # Bad action string; unsupported command
+
     event_changed_sensor = {
         "t": "event",
         "e": "changed",
@@ -279,6 +323,8 @@ async def test_deconz_alarm_events(hass, aioclient_mock, mock_deconz_websocket):
 
     assert len(captured_events) == 1
 
+    # Only care for changes to action
+
     event_changed_sensor = {
         "t": "event",
         "e": "changed",