diff --git a/hw/usb/dev-smartcard-reader.c b/hw/usb/dev-smartcard-reader.c
index 2131e33d27..f7c91230d5 100644
--- a/hw/usb/dev-smartcard-reader.c
+++ b/hw/usb/dev-smartcard-reader.c
@@ -1147,6 +1147,7 @@ static void ccid_unrealize(USBDevice *dev, Error **errp)
     USBCCIDState *s = USB_CCID_DEV(dev);
 
     ccid_bulk_in_clear(s);
+    object_unref(OBJECT(&s->bus));
 }
 
 static void ccid_flush_pending_answers(USBCCIDState *s)