{"id":"CVE-2023-51764","revision":"cac3b6aae82d4815a12cfb1b9bd28faa","records":[{"revision":"cac3b6aae82d4815a12cfb1b9bd28faa","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2023-51764","aliases":[],"title":"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 …","description":"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.","state":0,"publishedAt":"2023-12-24T00:00:00+00:00","modifiedAt":"2026-10-08T21:03:31.129+00:00","affected":[{"ecosystem":"Vendor product","name":"n/a","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"n/a\",\n                    \"product\": \"n/a\",\n                    \"versions\": [\n                        {\n                            \"version\": \"n/a\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://www.postfix.org/smtp-smuggling.html","https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/","http://www.openwall.com/lists/oss-security/2023/12/24/1","http://www.openwall.com/lists/oss-security/2023/12/25/1","https://bugzilla.redhat.com/show_bug.cgi?id=2255563","https://access.redhat.com/security/cve/CVE-2023-51764","https://fahrplan.events.ccc.de/congress/2023/fahrplan/events/11782.html","https://github.com/eeenvik1/CVE-2023-51764","https://github.com/duy-31/CVE-2023-51764","https://www.youtube.com/watch?v=V8KPV96g1To","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QRLF5SOS7TP5N7FQSEK2NFNB44ISVTZC/","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JQ5WXFCW2N6G2PH3JXDTYW5PH5EBQEGO/","https://lwn.net/Articles/956533/","https://www.openwall.com/lists/oss-security/2024/01/22/1","https://www.postfix.org/announcements/postfix-3.8.5.html","https://lists.debian.org/debian-lts-announce/2024/01/msg00020.html","http://www.openwall.com/lists/oss-security/2024/05/09/3"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2023-51764","license":"CVE Program Terms of Use","key":"cve-program:CVE-2023-51764","identifiers":["CVE-2023-51764"]},"retained":false,"historicalAffected":[]}],"coverage":[]}