CVE-2023-51766

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

Description

Exim before 4.97.1 allows SMTP smuggling in certain PIPELINING/CHUNKING configurations. 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 Exim supports <LF>.<CR><LF> but some other popular e-mail servers do not.

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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/2023/12/29/2
Source: cve@mitre.org
Mailing List Mitigation Third Party Advisory
http://www.openwall.com/lists/oss-security/2024/01/01/1
Source: cve@mitre.org
Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2024/01/01/2
Source: cve@mitre.org
Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2024/01/01/3
Source: cve@mitre.org
Mailing List Third Party Advisory
https://bugs.exim.org/show_bug.cgi?id=3063
Source: cve@mitre.org
Issue Tracking Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2255852
Source: cve@mitre.org
Issue Tracking Third Party Advisory
https://exim.org/static/doc/security/CVE-2023-51766.txt
Source: cve@mitre.org
Broken Link
https://fahrplan.events.ccc.de/congress/2023/fahrplan/events/11782.html
Source: cve@mitre.org
Technical Description
https://git.exim.org/exim.git/commit/5bb786d5ad568a88d50d15452aacc8404047e5ca
Source: cve@mitre.org
Patch
https://git.exim.org/exim.git/commit/cf1376206284f2a4f11e32d931d4aade34c206c5
Source: cve@mitre.org
Patch
https://github.com/Exim/exim/blob/master/doc/doc-txt/cve-2023-51766
Source: cve@mitre.org
Mitigation Vendor Advisory
https://lists.debian.org/debian-lts-announce/2024/01/msg00002.html
Source: cve@mitre.org
Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ORN7OKEQPPBKUHYRQ6LR5PSNBQVDHAWB/
Source: cve@mitre.org
Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QPDWHJPABVJCXDSNELSSVTIVAJU2MDUQ/
Source: cve@mitre.org
Mailing List Third Party Advisory
https://lwn.net/Articles/956533/
Source: cve@mitre.org
Third Party Advisory
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/2023/12/23/2
Source: cve@mitre.org
Issue Tracking Mailing List Third Party 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/2023/12/29/2
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Mitigation Third Party Advisory
http://www.openwall.com/lists/oss-security/2024/01/01/1
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2024/01/01/2
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2024/01/01/3
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://bugs.exim.org/show_bug.cgi?id=3063
Source: af854a3a-2127-422b-91ae-364da2661108
Issue Tracking Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2255852
Source: af854a3a-2127-422b-91ae-364da2661108
Issue Tracking Third Party Advisory
https://exim.org/static/doc/security/CVE-2023-51766.txt
Source: af854a3a-2127-422b-91ae-364da2661108
Broken Link
https://fahrplan.events.ccc.de/congress/2023/fahrplan/events/11782.html
Source: af854a3a-2127-422b-91ae-364da2661108
Technical Description
https://git.exim.org/exim.git/commit/5bb786d5ad568a88d50d15452aacc8404047e5ca
Source: af854a3a-2127-422b-91ae-364da2661108
Patch
https://git.exim.org/exim.git/commit/cf1376206284f2a4f11e32d931d4aade34c206c5
Source: af854a3a-2127-422b-91ae-364da2661108
Patch
https://github.com/Exim/exim/blob/master/doc/doc-txt/cve-2023-51766
Source: af854a3a-2127-422b-91ae-364da2661108
Mitigation Vendor Advisory
https://lists.debian.org/debian-lts-announce/2024/01/msg00002.html
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ORN7OKEQPPBKUHYRQ6LR5PSNBQVDHAWB/
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QPDWHJPABVJCXDSNELSSVTIVAJU2MDUQ/
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ORN7OKEQPPBKUHYRQ6LR5PSNBQVDHAWB/
Source: af854a3a-2127-422b-91ae-364da2661108
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QPDWHJPABVJCXDSNELSSVTIVAJU2MDUQ/
Source: af854a3a-2127-422b-91ae-364da2661108
https://lwn.net/Articles/956533/
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
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/2023/12/23/2
Source: af854a3a-2127-422b-91ae-364da2661108
Issue Tracking Mailing List Third Party Advisory
https://www.youtube.com/watch?v=V8KPV96g1To
Source: af854a3a-2127-422b-91ae-364da2661108
Exploit

42 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.3 / 10.0
EPSS (Exploit Probability)
1.6%
82th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

CWE-345

Affected Vendors

debian fedoraproject exim

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