diff --git a/services/smart.py b/services/smart.py
index c32d4e5..b0b700e 100644
--- a/services/smart.py
+++ b/services/smart.py
@@ -73,8 +73,8 @@ async def _run_smartctl(device: str) -> dict:
 
 def _parse_smart_json(device: str, data: dict) -> dict:
     """Extract relevant fields from smartctl JSON output."""
-    smart_support = data.get("smart_support", {})
-    is_supported = smart_support.get("available", True) if smart_support else True
+    smart_support = data.get("smart_support")
+    is_supported = smart_support.get("available", True) if isinstance(smart_support, dict) else False
     result: dict = {"device": device, "smart_supported": is_supported}
 
     # Identity — ATA vs SCSI field names