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Amazon Linux 2023 : sendmail, sendmail-cf, sendmail-milter (ALAS2023-2026-1818)

medium Nessus Plugin ID 319884

Synopsis

The remote Amazon Linux 2023 host is missing a security update.

Description

It is, therefore, affected by a vulnerability as referenced in the ALAS2023-2026-1818 advisory.

 sendmail through at least 8.14.7 allows SMTP smuggling in certain 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 sendmail supports <LF>.<CR><LF> but some other popular e-mail servers do not. (CVE-2023-51765)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Run 'dnf update sendmail --releasever 2023.12.20260608' or or 'dnf update --advisory ALAS2023-2026-1818 --releasever 2023.12.20260608' to update your system.

See Also

https://alas.aws.amazon.com//AL2023/ALAS2023-2026-1818.html

https://alas.aws.amazon.com/faqs.html

https://explore.alas.aws.amazon.com/CVE-2023-51765.html

Plugin Details

Severity: Medium

ID: 319884

File Name: al2023_ALAS2023-2026-1818.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 6/8/2026

Updated: 6/8/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 2.2

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.9

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N

CVSS Score Source: CVE-2023-51765

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Temporal Score: 4.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:sendmail-milter-debuginfo, p-cpe:/a:amazon:linux:sendmail-milter-devel, p-cpe:/a:amazon:linux:sendmail, p-cpe:/a:amazon:linux:sendmail-doc, p-cpe:/a:amazon:linux:sendmail-debugsource, p-cpe:/a:amazon:linux:sendmail-debuginfo, p-cpe:/a:amazon:linux:sendmail-cf, cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:sendmail-milter

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 6/8/2026

Vulnerability Publication Date: 12/24/2023

Reference Information

CVE: CVE-2023-51765