"SMTP Smuggling Flaw Exposes Email Security and Spoofing Risks"

A new cyber threat called SMTP smuggling has been discovered, allowing attackers to bypass email security measures and send spoofed emails from any address. This technique exploits inconsistencies in SMTP server handling of end-of-data sequences, similar to HTTP request smuggling. It affects servers from Microsoft, GMX, Cisco, Postfix, and Sendmail, undermining email authentication protocols like DKIM, DMARC, and SPF. While Microsoft and GMX have addressed the issue, Cisco considers it a feature, not a vulnerability, and recommends users adjust their settings to prevent exploitation.