diff --git a/lam/templates/login.php b/lam/templates/login.php
index 7808eb128..9f3c834c3 100644
--- a/lam/templates/login.php
+++ b/lam/templates/login.php
@@ -22,7 +22,7 @@ use ServerProfilePersistenceManager;
 
   This code is part of LDAP Account Manager (http://www.ldap-account-manager.org/)
   Copyright (C) 2003 - 2006  Michael Duergner
-                2005 - 2022  Roland Gruber
+                2005 - 2023  Roland Gruber
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -210,8 +210,12 @@ function display_LoginPage(?LAMLicenseValidator $licenseValidator, ?string $erro
     // save both in cookie
 	$cookieOptions = lamDefaultCookieOptions();
 	$cookieOptions['expires'] = 0;
-    setcookie("Key", base64_encode($key), $cookieOptions);
-    setcookie("IV", base64_encode($iv), $cookieOptions);
+	if ($key !== false) {
+		setcookie("Key", base64_encode($key), $cookieOptions);
+    }
+	if ($iv !== false) {
+		setcookie("IV", base64_encode($iv), $cookieOptions);
+    }
 
 	$serverProfilePersistenceManager = new ServerProfilePersistenceManager();
 	$profiles = $serverProfilePersistenceManager->getProfiles();
diff --git a/lam/templates/upload/massBuildAccounts.php b/lam/templates/upload/massBuildAccounts.php
index 522ebe588..5068b4710 100644
--- a/lam/templates/upload/massBuildAccounts.php
+++ b/lam/templates/upload/massBuildAccounts.php
@@ -131,8 +131,10 @@ if ($_FILES['inputfile'] && ($_FILES['inputfile']['size'] > 0)) {
 	$handle = fopen ($_FILES['inputfile']['tmp_name'], "r");
 	if ($handle !== false) {
 		if (($head = fgetcsv($handle, 2000)) !== false ) { // head row
-			foreach ($head as $i => $headItem) {
-				$ids[$headItem] = $i;
+			if (($head !== null) && ($head !== false)) {
+				foreach ($head as $i => $headItem) {
+					$ids[$headItem] = $i;
+				}
 			}
 		}
 		while (($line = fgetcsv($handle, 2000)) !== false ) { // account rows
@@ -193,7 +195,7 @@ if ($_FILES['inputfile'] && ($_FILES['inputfile']['size'] > 0)) {
 			if (sizeof($values_given) != sizeof($values_unique)) {
 				$duplicates = array();
 				foreach ($values_given as $key => $value) {
-					if (!isset($values_unique[$key])) {
+					if (!isset($values_unique[$key]) && ($value !== null)) {
 						$duplicates[] = htmlspecialchars($value);
 					}
 				}
diff --git a/phpstan.neon b/phpstan.neon
index 719c55f09..c23094336 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -23,15 +23,17 @@ parameters:
 		- '#Throwing object of an unknown class [a-zA-Z0-9\\_-]+.#'
 		- '#Parameter \#[0-9] \$[a-zA-Z_]+ of function [a-zA-Z_]+ expects [(]?callable.*#'
 		- '#Call to an undefined method object::.*#'
-		- '#Parameter \#2 \$string of function explode expects string, array<int, string>\|string given.#'
-		- '#Parameter \#2 \$result of function ldap_get_entries expects LDAP\\Result, array\|LDAP\\Result given.#'
+		- '#Parameter \#2 \$str of function explode expects string, array<int, string>\|string given.#'
+		- '#Parameter \#1 \$link_identifier of function ldap_.* expects resource, LDAP\\Connection given.#'
+		- '#Parameter \#1 \$link of function ldap_read expects array\|resource, LDAP\\Connection given.#'
 		- '#Cannot assign new offset to array<int, string>\|string.#'
-		- '#Cannot access offset .* on array\|int.#'
+		- '#Cannot access offset .* on mixed.#'
 		- '#Parameter \#1 \$haystack of function strpos expects string, int\|string given.#'
 		- '#Parameter \#1 \$string of function htmlspecialchars expects string, array<int, string>\|string given.#'
 		- '#Parameter \#1 \$name of function LAM\\ACCOUNTLIST\\search_username expects string, array<int, string>\|string given.#'
-		- '#Cannot access offset int\|string on mixed.#'
-		- '#Parameter \#1 \$array of function array_keys expects array, mixed given.#'
-		- '#Cannot access offset .+ on mixed.#'
+		- '#Parameter \#1 \$input of function array_keys expects array, mixed given.#'
+		- '#Offset int does not exist on array<int, string\|null>\|null.#'
 		- '#Argument of an invalid type mixed supplied for foreach, only iterables are supported.#'
-		- '#Parameter \#2 \$args of function call_user_func_array expects array<int\|string, mixed>, mixed given.#'
+		- '#Parameter \#2 \$parameters of function call_user_func_array expects array<int, mixed>, mixed given.#'
+		- '#Parameter \#1 \$input of method LAM\\AJAX\\Ajax::managePasswordChange\(\) expects array, mixed given.#'
+		- '#Strict comparison using === between array<string, class-string> and false will always evaluate to false.#'