diff --git a/python/nav/web/seeddb/page/netbox/forms.py b/python/nav/web/seeddb/page/netbox/forms.py
index 3dde54c40b..7f956a5cad 100644
--- a/python/nav/web/seeddb/page/netbox/forms.py
+++ b/python/nav/web/seeddb/page/netbox/forms.py
@@ -235,7 +235,7 @@ def clean(self):
             self._errors['profiles'] = self.error_class(
                 ["Category %s requires a management profile." % cat.id]
             )
-            del cleaned_data['profiles']
+            cleaned_data.pop('profiles', None)
 
         return cleaned_data
 
diff --git a/tests/integration/seeddb_test.py b/tests/integration/seeddb_test.py
index b34f996646..0a11c10811 100644
--- a/tests/integration/seeddb_test.py
+++ b/tests/integration/seeddb_test.py
@@ -49,6 +49,27 @@ def test_adding_netbox_with_invalid_ip_should_fail(db, client):
     assert 'Could not resolve name' in smart_str(response.content)
 
 
+def test_adding_netbox_with_invalid_profiles_should_fail(db, client):
+    url = reverse('seeddb-netbox-edit')
+    ip = "10.254.254.253"
+
+    response = client.post(
+        url,
+        follow=True,
+        data={
+            "ip": ip,
+            "room": "myroom",
+            "category": "GW",
+            "organization": "myorg",
+            "profiles": "-5785')) ORDER BY 1-- qAPu",
+        },
+    )
+
+    assert response.status_code == 200
+    assert 'Form was not valid' in smart_str(response.content)
+    assert not Netbox.objects.filter(ip=ip).exists()
+
+
 @pytest.fixture()
 def netbox(management_profile):
     box = Netbox(