diff --git a/apps/dav/lib/CalDAV/CalDavBackend.php b/apps/dav/lib/CalDAV/CalDavBackend.php
index c57d3a2764f1e..1d526d89e6b52 100644
--- a/apps/dav/lib/CalDAV/CalDavBackend.php
+++ b/apps/dav/lib/CalDAV/CalDavBackend.php
@@ -3139,7 +3139,9 @@ public function pruneOutdatedSyncTokens(int $keep = 10_000): int {
 		$query->select($query->func()->max('id'))
 			->from('calendarchanges');
 
-		$maxId =  $query->executeQuery()->fetchOne();
+		$result = $query->executeQuery();
+		$maxId = (int) $result->fetchOne();
+		$result->closeCursor();
 		if (!$maxId || $maxId < $keep) {
 		    return 0;
 		}
diff --git a/apps/dav/lib/CardDAV/CardDavBackend.php b/apps/dav/lib/CardDAV/CardDavBackend.php
index 1be1ce3f18f01..045ad4d1385ba 100644
--- a/apps/dav/lib/CardDAV/CardDavBackend.php
+++ b/apps/dav/lib/CardDAV/CardDavBackend.php
@@ -1404,7 +1404,9 @@ public function pruneOutdatedSyncTokens(int $keep = 10_000): int {
 		$query->select($query->func()->max('id'))
 			->from('addressbookchanges');
 
-		$maxId =  $query->executeQuery()->fetchOne();
+		$result = $query->executeQuery();
+		$maxId = (int) $result->fetchOne();
+		$result->closeCursor();
 		if (!$maxId || $maxId < $keep) {
 		    return 0;
 		}