diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 5a388126..0889d216 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -9,6 +9,7 @@ This document describes changes between each past release.
 **Bug fix**
 
 - Update the `last_modified` value when updating the collection status and signature (#97)
+- Prevents crash with events on ``default`` bucket on Kinto < 3.3
 
 
 0.7.0 (2016-06-28)
diff --git a/kinto_signer/__init__.py b/kinto_signer/__init__.py
index 7aac99cd..3015dd9a 100644
--- a/kinto_signer/__init__.py
+++ b/kinto_signer/__init__.py
@@ -19,6 +19,12 @@ def on_collection_changed(event, resources):
     and update the destination.
     """
     payload = event.payload
+
+    if 'bucket_id' not in payload:
+        # Safety check for kinto < 3.3 where events have incoherent payloads
+        # on default bucket.
+        return
+
     key = "/buckets/{bucket_id}/collections/{collection_id}".format(**payload)
     resource = resources.get(key)
 
diff --git a/kinto_signer/tests/test_plugin_setup.py b/kinto_signer/tests/test_plugin_setup.py
index 42f18698..8882aa3b 100644
--- a/kinto_signer/tests/test_plugin_setup.py
+++ b/kinto_signer/tests/test_plugin_setup.py
@@ -151,6 +151,11 @@ def test_updater_is_called_when_resource_and_status_matches(self):
         mocked = self.updater_mocked.return_value
         assert mocked.sign_and_update_destination.called
 
+    def test_updater_does_not_fail_when_payload_is_inconsistent(self):
+        # This happens with events on default bucket for kinto < 3.3
+        evt = mock.MagicMock(payload={"subpath": "collections/boom"})
+        on_collection_changed(evt, resources=utils.parse_resources("a/b;c/d"))
+
 
 class SigningErrorTest(BaseWebTest, unittest.TestCase):
     def test_returns_503_if_autograph_cannot_be_reached(self):