diff --git a/apps/dav/lib/CalDAV/CalDavBackend.php b/apps/dav/lib/CalDAV/CalDavBackend.php
index 7094358a2c6..67d36e351a8 100644
--- a/apps/dav/lib/CalDAV/CalDavBackend.php
+++ b/apps/dav/lib/CalDAV/CalDavBackend.php
@@ -1901,6 +1901,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 
 		$result = $outerQuery->executeQuery();
 		$calendarObjects = $result->fetchAll();
+		$result->closeCursor();
 
 		return array_map(function ($o) {
 			$calendarData = Reader::read($o['calendardata']);
@@ -2615,6 +2616,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 				'size' => (int)$row['size'],
 			];
 		}
+		$stmt->closeCursor();
 
 		return $result;
 	}
@@ -2994,6 +2996,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 			->executeQuery();
 
 		$ids = $result->fetchAll();
+		$result->closeCursor();
 		foreach ($ids as $id) {
 			$this->deleteCalendar(
 				$id['id'],