aiosmtpd vulnerable to SMTP smuggling
### Summary
aiosmtpd is vulnerable to inbound SMTP smuggling. SMTP smuggling is a novel vulnerability based on not so novel interpretation differences of the SMTP protocol. By exploiting SMTP smuggling, an attacker may send smuggle/spoof e-mails with fake sender addresses, allowing advanced phishing attacks. This issue also existed in other SMTP software like Postfix (
https://www.postfix.org/smtp-smuggling.html)
### Details
Detailed information on SMTP smuggling can be found in the full blog post (
https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/) or on the Postfix homepage (
https://www.postfix.org/smtp-smuggling.html) (and soon on the official website
https://smtpsmuggling.com/)
### Impact
With the right SMTP server constellation, an attacker can send spoofed e-mails to inbound/receiving aiosmtpd instances.