CVE-2023-51764

Summary

CVE-2023-51764 is a vulnerability affecting Postfix email servers up to version 3.8.5. It enables SMTP smuggling, allowing remote attackers to inject e-mail messages with spoofed MAIL FROM addresses, bypassing SPF protection mechanisms. This occurs due to Postfix's support for <LF>.<CR><LF>, which some other popular e-mail servers do not. To mitigate this issue, administrators should configure smtpd_data_restrictions=reject_unauth_pipelining and smtpd_discard_ehlo_keywords=chunking, or enable smtpd_forbid_bare_newline=yes with a Postfix minimum version of 3.5.23, 3.6.13, 3.7.9, 3.8.4, or 3.9.

Prevent cyber attacks with Recorded Future by prioritizing and patching critical vulnerabilities being exploited by threat actors targeting your industry. Book your demo to learn more.