CVE-2023-51764

5.3 MEDIUM
Published: December 24, 2023 Modified: November 04, 2025
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
http://www.openwall.com/lists/oss-security/2023/12/24/1
Source: cve@mitre.org
Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2023/12/25/1
Source: cve@mitre.org
Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2024/05/09/3
Source: cve@mitre.org
https://access.redhat.com/security/cve/CVE-2023-51764
Source: cve@mitre.org
Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2255563
Source: cve@mitre.org
Issue Tracking Third Party Advisory
https://fahrplan.events.ccc.de/congress/2023/fahrplan/events/11782.html
Source: cve@mitre.org
Technical Description
https://github.com/duy-31/CVE-2023-51764
Source: cve@mitre.org
Exploit Third Party Advisory
https://github.com/eeenvik1/CVE-2023-51764
Source: cve@mitre.org
Exploit Third Party Advisory
https://lists.debian.org/debian-lts-announce/2024/01/msg00020.html
Source: cve@mitre.org
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JQ5WXFCW2N6G2PH3JXDTYW5PH5EBQEGO/
Source: cve@mitre.org
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QRLF5SOS7TP5N7FQSEK2NFNB44ISVTZC/
Source: cve@mitre.org
https://lwn.net/Articles/956533/
Source: cve@mitre.org
https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/
Source: cve@mitre.org
Technical Description Third Party Advisory
https://www.openwall.com/lists/oss-security/2024/01/22/1
Source: cve@mitre.org
https://www.postfix.org/announcements/postfix-3.8.5.html
Source: cve@mitre.org
https://www.postfix.org/smtp-smuggling.html
Source: cve@mitre.org
Exploit Mitigation Vendor Advisory
https://www.youtube.com/watch?v=V8KPV96g1To
Source: cve@mitre.org
Exploit
http://www.openwall.com/lists/oss-security/2023/12/24/1
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2023/12/25/1
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2024/05/09/3
Source: af854a3a-2127-422b-91ae-364da2661108
https://access.redhat.com/security/cve/CVE-2023-51764
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2255563
Source: af854a3a-2127-422b-91ae-364da2661108
Issue Tracking Third Party Advisory
https://fahrplan.events.ccc.de/congress/2023/fahrplan/events/11782.html
Source: af854a3a-2127-422b-91ae-364da2661108
Technical Description
https://github.com/duy-31/CVE-2023-51764
Source: af854a3a-2127-422b-91ae-364da2661108
Exploit Third Party Advisory
https://github.com/eeenvik1/CVE-2023-51764
Source: af854a3a-2127-422b-91ae-364da2661108
Exploit Third Party Advisory
https://lists.debian.org/debian-lts-announce/2024/01/msg00020.html
Source: af854a3a-2127-422b-91ae-364da2661108
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JQ5WXFCW2N6G2PH3JXDTYW5PH5EBQEGO/
Source: af854a3a-2127-422b-91ae-364da2661108
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QRLF5SOS7TP5N7FQSEK2NFNB44ISVTZC/
Source: af854a3a-2127-422b-91ae-364da2661108
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JQ5WXFCW2N6G2PH3JXDTYW5PH5EBQEGO/
Source: af854a3a-2127-422b-91ae-364da2661108
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QRLF5SOS7TP5N7FQSEK2NFNB44ISVTZC/
Source: af854a3a-2127-422b-91ae-364da2661108
https://lwn.net/Articles/956533/
Source: af854a3a-2127-422b-91ae-364da2661108
https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/
Source: af854a3a-2127-422b-91ae-364da2661108
Technical Description Third Party Advisory
https://www.openwall.com/lists/oss-security/2024/01/22/1
Source: af854a3a-2127-422b-91ae-364da2661108
https://www.postfix.org/announcements/postfix-3.8.5.html
Source: af854a3a-2127-422b-91ae-364da2661108
https://www.postfix.org/smtp-smuggling.html
Source: af854a3a-2127-422b-91ae-364da2661108
Exploit Mitigation Vendor Advisory
https://www.youtube.com/watch?v=V8KPV96g1To
Source: af854a3a-2127-422b-91ae-364da2661108
Exploit

36 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.3 / 10.0
EPSS (Exploit Probability)
20.3%
95th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

CWE-345

Affected Vendors

redhat postfix fedoraproject

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