Cron triggered by localhost/cron.php turns $base_url into localhost

The cron job in /etc/cron.d/drupal triggers the cron via http://localhost/cron.php.
I run the subscriptions module which sends out emails every cron run. The links in the email sent by this module all start with http://localhost/... as if the $base_url is localhost. Even though in setting.php, the $base_url is set with my own domain name, it still spits out links with localhost.

So, I removed the cronjob from the drupal file. Altering could work as well obviously, but I trigger cron from a remote server.

This report can be considered is a general report, rather than a bug report.