diff --git a/inc/mod/pages.php b/inc/mod/pages.php
index 7b64663c..050e1216 100644
--- a/inc/mod/pages.php
+++ b/inc/mod/pages.php
@@ -1655,7 +1655,7 @@ function mod_merge(Context $ctx, $originBoard, $postID) {
         error($config['error']['noaccess']);
 
     $query = prepare(sprintf('SELECT * FROM ``posts_%s`` WHERE `id` = :id AND `thread` IS NULL', $originBoard));
-    $query->bindValue(':id', $postID);
+    $query->bindValue(':id', (int)$postID, \PDO::PARAM_INT);
     $query->execute() or error(db_error($query));
     if (!$post = $query->fetch(PDO::FETCH_ASSOC)) {
         error($config['error']['404']);