diff --git a/aleksis/apps/kort/models/sdm.py b/aleksis/apps/kort/models/sdm.py
index f89ff06248c33cdca5f876e397848b51160abe2f..240eaf501717d13d79b9c21c57f4032edfef45e8 100644
--- a/aleksis/apps/kort/models/sdm.py
+++ b/aleksis/apps/kort/models/sdm.py
@@ -32,6 +32,9 @@ class NfcSdmAuthenticator(ObjectAuthenticator):
         except Card.DoesNotExist:
             return False
 
+        if not card.is_valid:
+            raise BadRequest("Card is not valid")
+
         if obj is None:
             obj = card.person