diff --git a/typo3/sysext/core/Classes/Error/ErrorHandler.php b/typo3/sysext/core/Classes/Error/ErrorHandler.php
index 80885d96268940c5d05153d3e44ea430677e10b3..27f0c9aee59997dbe33b7694fb86c56045a9d039 100644
--- a/typo3/sysext/core/Classes/Error/ErrorHandler.php
+++ b/typo3/sysext/core/Classes/Error/ErrorHandler.php
@@ -18,6 +18,7 @@ use Psr\Log\LoggerAwareInterface;
 use Psr\Log\LoggerAwareTrait;
 use TYPO3\CMS\Core\Database\ConnectionPool;
 use TYPO3\CMS\Core\Log\LogLevel;
+use TYPO3\CMS\Core\Messaging\FlashMessage;
 use TYPO3\CMS\Core\TimeTracker\TimeTracker;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
 
@@ -113,13 +114,16 @@ class ErrorHandler implements ErrorHandlerInterface, LoggerAwareInterface
         switch ($errorLevel) {
             case E_USER_ERROR:
             case E_RECOVERABLE_ERROR:
+                // no $flashMessageSeverity, as there will be no flash message for errors
                 $severity = 2;
                 break;
             case E_USER_WARNING:
             case E_WARNING:
+                $flashMessageSeverity = FlashMessage::WARNING;
                 $severity = 1;
                 break;
             default:
+                $flashMessageSeverity = FlashMessage::NOTICE;
                 $severity = 0;
         }
         $logTitle = 'Core: Error handler (' . TYPO3_MODE . ')';
@@ -150,7 +154,7 @@ class ErrorHandler implements ErrorHandlerInterface, LoggerAwareInterface
                         \TYPO3\CMS\Core\Messaging\FlashMessage::class,
                         $message,
                         $errorLevels[$errorLevel],
-                        $severity
+                        $flashMessageSeverity
                     );
             /** @var $flashMessageService \TYPO3\CMS\Core\Messaging\FlashMessageService */
             $flashMessageService = GeneralUtility::makeInstance(\TYPO3\CMS\Core\Messaging\FlashMessageService::class);