--- a/src/plugins/fts/fts-api.c	2018-04-30 21:52:04.000000000 +0800
+++ b/src/plugins/fts/fts-api.c	2019-04-04 17:51:00.170000000 +0800
@@ -425,7 +425,7 @@ bool fts_index_get_header(struct mailbox
 		i_zero(hdr_r);
 		ret = FALSE;
 	} else {
-		memcpy(hdr_r, data, data_size);
+		memcpy(hdr_r, data, sizeof(*hdr_r));
 		ret = TRUE;
 	}
 	mail_index_view_close(&view);
