Steps to reproduce the issue

install Joomla 4 as normal

At command line run

php /administrator/index.php

(Believe it or not, People do this. They use it for things like cron jobs in custom extensions etc)

Expected result

Nothing returned from the request (like Joomla 3)

Actual result

Notice: Undefined index: HTTP_HOST in /home/joomla4beta1/public_html/libraries/src/Uri/Uri.php on line 103

Warning: session_name(): Cannot change session name when headers already sent in /home/joomla4beta1/public_html/libraries/vendor/joomla/session/src/Storage/NativeStorage.php on line 405
RuntimeException {#184
  #message: "Failed to start the session because headers have already been sent by "/home/joomla4beta1/public_html/libraries/src/Uri/Uri.php" at line 103."
  #code: 0
  #file: "./libraries/vendor/joomla/session/src/Storage/NativeStorage.php"
  #line: 473
  -previous: RuntimeException {#170
    #message: "Failed to start the session because headers have already been sent by "/home/joomla4beta1/public_html/libraries/src/Uri/Uri.php" at line 103."
    #code: 0
    #file: "./libraries/vendor/joomla/session/src/Storage/NativeStorage.php"
    #line: 473
    trace: {
      ./libraries/vendor/joomla/session/src/Storage/NativeStorage.php:473 { …}
      ./libraries/src/Session/Storage/JoomlaStorage.php:305 {
        Joomla\CMS\Session\Storage\JoomlaStorage->start(): void^
        ›
        › parent::start();
        ›
      }
      ./libraries/vendor/joomla/session/src/Session.php:405 { …}
      ./libraries/vendor/joomla/session/src/Session.php:332 { …}
      ./libraries/src/Session/Session.php:201 { …}
      ./libraries/src/Application/CMSApplication.php:627 { …}
      ./libraries/src/Application/AdministratorApplication.php:161 { …}
      ./libraries/src/Application/CMSApplication.php:266 { …}
      ./administrator/includes/app.php:63 { …}
      ./administrator/index.php:36 { …}
    }
  }
  trace: {
    ./libraries/vendor/joomla/session/src/Storage/NativeStorage.php:473 { …}
    ./libraries/src/Session/Storage/JoomlaStorage.php:305 {
      Joomla\CMS\Session\Storage\JoomlaStorage->start(): void^
      ›
      › parent::start();
      ›
    }
    ./libraries/vendor/joomla/session/src/Session.php:405 { …}
    ./libraries/vendor/joomla/session/src/Session.php:332 { …}
    ./libraries/src/Session/Session.php:201 { …}
    ./libraries/src/Factory.php:339 { …}
    ./libraries/src/Application/AdministratorApplication.php:228 { …}
    ./libraries/src/Error/Renderer/HtmlRenderer.php:47 { …}
    ./libraries/src/Exception/ExceptionHandler.php:128 { …}
    ./libraries/src/Exception/ExceptionHandler.php:71 { …}
    ./libraries/src/Application/CMSApplication.php:299 { …}
    ./administrator/includes/app.php:63 { …}
    ./administrator/index.php:36 { …}
  }
}

System information (as much as possible)

PHP 7.4.13 (cli) (built: Dec 23 2020 11:21:05) ( NTS )
Copyright (c) The PHP Group
Zend Engine v3.4.0, Copyright (c) Zend Technologies
    with Zend OPcache v7.4.13, Copyright (c), by Zend Technologies

Additional comments