diff --git a/src/Auth/AclTrait.php b/src/Auth/AclTrait.php
index 705d015a..f747f117 100644
--- a/src/Auth/AclTrait.php
+++ b/src/Auth/AclTrait.php
@@ -176,7 +176,7 @@ protected function _check(array $userRoles, array $params) {
 		}
 
 		$iniKey = $this->_constructIniKey($params);
-		if (empty($this->_acl[$iniKey])) {
+		if ($iniKey === null || empty($this->_acl[$iniKey])) {
 			return false;
 		}
 
@@ -420,10 +420,13 @@ protected function _deconstructIniKey($key) {
 	 * Constructs an ACL INI section key from a given Request.
 	 *
 	 * @param array $params The request params
-	 * @return string Hash with named keys for controller, plugin and prefix
+	 * @return string|null Hash with named keys for controller, plugin and prefix
 	 */
-	protected function _constructIniKey($params) {
-		$res = $params['controller'];
+	protected function _constructIniKey($params): ?string {
+		$res = $params['controller'] ?? null;
+		if ($res === null) {
+			return null;
+		}
 		if (!empty($params['prefix'])) {
 			$res = $params['prefix'] . "/$res";
 		}