diff --git a/src/task_scheduler.py b/src/task_scheduler.py
index 6c8ab148a..b84632e43 100644
--- a/src/task_scheduler.py
+++ b/src/task_scheduler.py
@@ -236,6 +236,29 @@ def _digest_windows(now):
     ]
 
 
+def _checkin_calendar_events(db, owner, start, end):
+    """Calendar events in [start, end] for ONE owner, for the check-in digest.
+
+    Ownership lives on CalendarCal.owner; events inherit it via calendar_id.
+    The digest query had no owner scope, so it pulled EVERY user's events into
+    one user's check-in (a cross-tenant leak of summaries/locations). Scope it
+    by joining CalendarCal, mirroring routes/calendar_routes.list_events.
+    """
+    from core.database import CalendarEvent as _CE, CalendarCal as _CC
+    return (
+        db.query(_CE)
+        .join(_CC, _CE.calendar_id == _CC.id)
+        .filter(
+            _CC.owner == owner,
+            _CE.dtstart >= start,
+            _CE.dtstart <= end,
+            _CE.status != "cancelled",
+        )
+        .order_by(_CE.dtstart)
+        .all()
+    )
+
+
 class TaskScheduler:
     def __init__(self, session_manager):
         self._session_manager = session_manager
@@ -1127,11 +1150,7 @@ class TaskScheduler:
                     # Strip timezone for naive DB comparison
                     _s = start.replace(tzinfo=None) if start.tzinfo else start
                     _e = end.replace(tzinfo=None) if end.tzinfo else end
-                    evs = _db.query(_CE).filter(
-                        _CE.dtstart >= _s,
-                        _CE.dtstart <= _e,
-                        _CE.status != "cancelled",
-                    ).order_by(_CE.dtstart).all()
+                    evs = _checkin_calendar_events(_db, task.owner, _s, _e)
                     if not evs:
                         continue
                     # Group by importance for richer output
diff --git a/tests/test_checkin_digest_owner_scope.py b/tests/test_checkin_digest_owner_scope.py
new file mode 100644
index 000000000..a2e8ebb17
--- /dev/null
+++ b/tests/test_checkin_digest_owner_scope.py
@@ -0,0 +1,70 @@
+"""Check-in calendar digest must be scoped to the task owner.
+
+The digest query selected CalendarEvent with no owner scope, so a scheduled
+check-in for one user pulled EVERY user's calendar events (summaries,
+locations) into their digest — a cross-tenant leak. Ownership lives on
+CalendarCal.owner; the query must join it, like routes/calendar_routes.
+"""
+import tempfile
+import uuid
+from datetime import datetime
+
+import pytest
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+from sqlalchemy.pool import NullPool
+
+import core.database as cdb
+from core.database import CalendarEvent, CalendarCal
+from src.task_scheduler import _checkin_calendar_events
+
+_TMPDB = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
+_ENGINE = create_engine(f"sqlite:///{_TMPDB.name}", connect_args={"check_same_thread": False}, poolclass=NullPool)
+cdb.Base.metadata.create_all(_ENGINE)
+_TS = sessionmaker(bind=_ENGINE, autoflush=False, autocommit=False)
+
+
+def _seed():
+    db = _TS()
+    try:
+        db.query(CalendarEvent).delete(); db.query(CalendarCal).delete()
+        db.add(CalendarCal(id="calA", owner="alice", name="A"))
+        db.add(CalendarCal(id="calB", owner="bob", name="B"))
+        db.add(CalendarEvent(uid="a1", calendar_id="calA", summary="Alice mtg",
+                             dtstart=datetime(2026, 6, 10, 9, 0),
+                             dtend=datetime(2026, 6, 10, 10, 0), status="confirmed"))
+        db.add(CalendarEvent(uid="b1", calendar_id="calB", summary="Bob secret",
+                             dtstart=datetime(2026, 6, 10, 10, 0),
+                             dtend=datetime(2026, 6, 10, 11, 0), status="confirmed"))
+        db.commit()
+    finally:
+        db.close()
+
+
+def test_digest_only_returns_owner_events():
+    _seed()
+    db = _TS()
+    try:
+        s, e = datetime(2026, 6, 1), datetime(2026, 6, 30)
+        alice = _checkin_calendar_events(db, "alice", s, e)
+        assert [ev.summary for ev in alice] == ["Alice mtg"]  # not Bob's
+        bob = _checkin_calendar_events(db, "bob", s, e)
+        assert [ev.summary for ev in bob] == ["Bob secret"]
+    finally:
+        db.close()
+
+
+def test_cancelled_excluded_and_window_respected():
+    _seed()
+    db = _TS()
+    try:
+        db2 = _TS()
+        db2.add(CalendarEvent(uid="a2", calendar_id="calA", summary="cancelled",
+                              dtstart=datetime(2026, 6, 11),
+                              dtend=datetime(2026, 6, 11, 1, 0), status="cancelled"))
+        db2.commit(); db2.close()
+        s, e = datetime(2026, 6, 1), datetime(2026, 6, 30)
+        out = _checkin_calendar_events(db, "alice", s, e)
+        assert "cancelled" not in [ev.summary for ev in out]
+    finally:
+        db.close()