diff --git a/src/pretix/api/views/checkin.py b/src/pretix/api/views/checkin.py
index 866e7a639d..861459018f 100644
--- a/src/pretix/api/views/checkin.py
+++ b/src/pretix/api/views/checkin.py
@@ -35,6 +35,7 @@ from django.http import Http404
 from django.shortcuts import get_object_or_404
 from django.utils.functional import cached_property
 from django.utils.timezone import now
+from django.utils.translation import gettext
 from django_filters.rest_framework import DjangoFilterBackend, FilterSet
 from django_scopes import scopes_disabled
 from packaging.version import parse
@@ -586,6 +587,32 @@ def _redeem_process(*, checkinlists, raw_barcode, answers_data, datetime, force,
                     'list': MiniCheckinListSerializer(list_by_event[revoked_matches[0].event_id]).data,
                 }, status=400)
         else:
+            if media.linked_orderposition.order.event_id not in list_by_event:
+                # Medium exists but connected ticket is for the wrong event
+                if not simulate:
+                    checkinlists[0].event.log_action('pretix.event.checkin.unknown', data={
+                        'datetime': datetime,
+                        'type': checkin_type,
+                        'list': checkinlists[0].pk,
+                        'barcode': raw_barcode,
+                        'searched_lists': [cl.pk for cl in checkinlists]
+                    }, user=user, auth=auth)
+                    Checkin.objects.create(
+                        position=None,
+                        successful=False,
+                        error_reason=Checkin.REASON_INVALID,
+                        error_explanation=gettext('Medium connected to other event'),
+                        **common_checkin_args,
+                    )
+                return Response({
+                    'detail': 'Not found.',  # for backwards compatibility
+                    'status': 'error',
+                    'reason': Checkin.REASON_INVALID,
+                    'reason_explanation': gettext('Medium connected to other event'),
+                    'require_attention': False,
+                    'checkin_texts': [],
+                    'list': MiniCheckinListSerializer(checkinlists[0]).data,
+                }, status=404)
             op_candidates = [media.linked_orderposition]
             if list_by_event[media.linked_orderposition.order.event_id].addon_match:
                 op_candidates += list(media.linked_orderposition.addons.all())
diff --git a/src/tests/api/test_checkinrpc.py b/src/tests/api/test_checkinrpc.py
index 7624098f2e..4e287bd8f5 100644
--- a/src/tests/api/test_checkinrpc.py
+++ b/src/tests/api/test_checkinrpc.py
@@ -308,6 +308,25 @@ def test_by_medium_not_connected(token_client, organizer, clist, event, order):
     assert resp.data['reason'] == 'invalid'
 
 
+@pytest.mark.django_db
+def test_by_medium_wrong_event(token_client, organizer, clist, event, order2):
+    with scopes_disabled():
+        ReusableMedium.objects.create(
+            type="barcode",
+            identifier="abcdef",
+            organizer=organizer,
+            linked_orderposition=order2.positions.first(),
+        )
+    resp = _redeem(token_client, organizer, clist, "abcdef", {"source_type": "barcode"})
+    assert resp.status_code == 404
+    assert resp.data['status'] == 'error'
+    assert resp.data['reason'] == 'invalid'
+    with scopes_disabled():
+        ci = clist.checkins.get()
+    assert ci.raw_barcode == "abcdef"
+    assert ci.raw_source_type == "barcode"
+
+
 @pytest.mark.django_db
 def test_by_medium_wrong_type(token_client, organizer, clist, event, order):
     with scopes_disabled():