diff --git a/misc/lnstat.c b/misc/lnstat.c
index bd19cc10..90198b73 100644
--- a/misc/lnstat.c
+++ b/misc/lnstat.c
@@ -166,7 +166,7 @@ static struct table_hdr *build_hdr_string(struct lnstat_file *lnstat_files,
 
 	for (i = 0; i < HDR_LINES; i++) {
 		th.hdr[i] = malloc(HDR_LINE_LENGTH);
-		memset(th.hdr[i], 0, sizeof(th.hdr[i]));
+		memset(th.hdr[i], 0, HDR_LINE_LENGTH);
 	}
 
 	for (i = 0; i < fps->num; i++) {