authentik invitation expiry is delayed by at least 5 minutes

@@ -38,7 +38,7 @@ def get_invite(self) -> Invitation | None:
         if not token:
             return None
         try:
-            invite: Invitation = Invitation.objects.filter(pk=token).first()
+            invite: Invitation | None = Invitation.filter_not_expired(pk=token).first()
         except ValidationError:
             self.logger.debug("invalid invitation", token=token)
             return None

@@ -1,9 +1,11 @@
 """invitation tests"""
 
+from datetime import timedelta
 from unittest.mock import MagicMock, patch
 
 from django.urls import reverse
 from django.utils.http import urlencode
+from django.utils.timezone import now
 from guardian.shortcuts import get_anonymous_user
 from rest_framework.test import APITestCase
 
@@ -79,6 +81,31 @@ def test_without_invitation_continue(self):
         self.stage.continue_flow_without_invitation = False
         self.stage.save()
 
+    def test_with_invitation_expired(self):
+        """Test with invitation, expired"""
+        plan = FlowPlan(flow_pk=self.flow.pk.hex, bindings=[self.binding], markers=[StageMarker()])
+        session = self.client.session
+        session[SESSION_KEY_PLAN] = plan
+        session.save()
+
+        data = {"foo": "bar"}
+        invite = Invitation.objects.create(
+            created_by=get_anonymous_user(),
+            fixed_data=data,
+            expires=now() - timedelta(hours=1),
+        )
+
+        base_url = reverse("authentik_api:flow-executor", kwargs={"flow_slug": self.flow.slug})
+        args = urlencode({QS_INVITATION_TOKEN_KEY: invite.pk.hex})
+        response = self.client.get(base_url + f"?query={args}")
+
+        self.assertEqual(response.status_code, 200)
+        self.assertStageResponse(
+            response,
+            flow=self.flow,
+            component="ak-stage-access-denied",
+        )
+
     def test_with_invitation_get(self):
         """Test with invitation, check data in session"""
         plan = FlowPlan(flow_pk=self.flow.pk.hex, bindings=[self.binding], markers=[StageMarker()])

@@ -0,0 +1,27 @@
+# CVE-2025-64708
+
+_Reported by [@melizeche](https://github.com/melizeche)_
+
+## Invitation expiry is delayed by at least 5 minutes
+
+### Summary
+
+In previous authentik versions, invitations were considered valid regardless if they are expired or not, thus relying on background tasks to clean up expired ones. In a normal scenario this can take up to 5 minutes because the cleanup of expired objects is scheduled to run every 5 minutes. However, with a large amount of tasks in the backlog, this might take longer.
+
+### Patches
+
+authentik 2025.8.5 and 2025.10.2 fix this issue; for other versions the workaround below can be used.
+
+### Workarounds
+
+You can create a policy that explicitly checks whether the invitation is still valid, and then bind it to the invitation stage on your invitation flow, and deny access if the invitation is not valid.
+
+```python
+return not context['flow_plan'].context['invitation'].is_expired
+```
+
+### For more information
+
+If you have any questions or comments about this advisory:
+
+- Email us at [security@goauthentik.io](mailto:security@goauthentik.io).