diff --git a/inc/mod/auth.php b/inc/mod/auth.php
index 70cf23ff..f6a65db2 100644
--- a/inc/mod/auth.php
+++ b/inc/mod/auth.php
@@ -10,7 +10,7 @@ use Vichan\Functions\Net;
 defined('TINYBOARD') or exit;
 
 // create a hash/salt pair for validate logins
-function mkhash(string $username, string $password, mixed $salt = false): array|string {
+function mkhash(string $username, ?string $password, mixed $salt = false): array|string {
 	global $config;
 
 	if (!$salt) {