To deliver mails sent locally through sendmail or SMTP, our web servers do use a local Postfix installation each. This is used to deliver mails sent through web applications running on those servers. Under certain circumstances, it might be possible to inject a second email into the delivery process (details) through an application, for example by using a tailored message within an unsecured contact form.
Therefore, we changed the configuration to forbid bare newlines to close this loophole under all circumstances. Standard SMTP implementations will not be affected, so we do not expect any drawbacks. Nevertheless, should you run into a problem with your application, please contact us to decide the proper proceedings.
Reference #1480
