Postfix through 3.8.5 allows SMTP smuggling unless configured with smtpd_data_restrictions=reject_unauth_pipelining and smtpd_discard_ehlo_keywords=chunking (or certain other options that exist in recent versions). Remote attackers can use a published exploitation technique to inject e-mail messages with a spoofed MAIL FROM address, allowing bypass of an SPF protection mechanism. This occurs because Postfix supports <LF>.<CR><LF> but some other popular e-mail servers do not. To prevent attack variants (by always disallowing <LF> without <CR>), a different solution is required, such as the smtpd_forbid_bare_newline=yes option with a Postfix minimum version of 3.5.23, 3.6.13, 3.7.9, 3.8.4, or 3.9.
History

No history.

cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published: 2023-12-24T00:00:00

Updated: 2024-08-02T22:48:11.093Z

Reserved: 2023-12-24T00:00:00

Link: CVE-2023-51764

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2023-12-24T05:15:08.273

Modified: 2024-06-10T18:15:23.843

Link: CVE-2023-51764

cve-icon Redhat

Severity : Moderate

Publid Date: 2023-12-18T00:00:00Z

Links: CVE-2023-51764 - Bugzilla