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Amazon Linux 2023 : libnetapi, libnetapi-devel, libsmbclient (ALAS2023-2026-2135)

medium Nessus Plugin ID 345766

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Synopsis

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

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-2135 advisory.

 A flaw was found in samba's pam_winbind. When mkhomedir is enabled, pam_winbind chowns the target account's home directory without validating the path is not a critical system directory such as /. On affected systems, accounts with / as their home directory (a common default for system accounts) can have this triggered not only by root, but by a non-root user holding a narrow sudo delegation to run commands as that account, causing ownership of / to change and resulting in severe denial of service (SSH, sudo, and package-manager failures). The change does not grant write access to / (which ships with restrictive 0555 permissions on RHEL), so the impact is availability loss rather than further privilege escalation.
 (CVE-2026-15779)

 DNS signing DoS via TKEY name cache exhaustion

 NOTE: https://www.samba.org/samba/security/CVE-2026-58218-advisory.html (CVE-2026-58218)

 TSIG packet with name compression can crash DNS (CVE-2026-6949)

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

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

Solution

Run 'dnf update samba --releasever 2023.12.20260914' or or 'dnf update --advisory ALAS2023-2026-2135 --releasever 2023.12.20260914' to update your system.

See Also

https://alas.aws.amazon.com//AL2023/ALAS2023-2026-2135.html

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

https://explore.alas.aws.amazon.com/CVE-2026-15779.html

https://explore.alas.aws.amazon.com/CVE-2026-58218.html

https://explore.alas.aws.amazon.com/CVE-2026-6949.html

Plugin Details

Severity: Medium

ID: 345766

File Name: al2023_ALAS2023-2026-2135.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 9/14/2026

Updated: 9/14/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.5

Percentile: 51.88

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-6949

CVSS v3

Risk Factor: Medium

Base Score: 6.1

Temporal Score: 5.3

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

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

CVSS Score Source: CVE-2026-15779

Vulnerability Information

CPE: cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:libnetapi-debuginfo, p-cpe:/a:amazon:linux:libnetapi-devel, p-cpe:/a:amazon:linux:libnetapi, p-cpe:/a:amazon:linux:libsmbclient-debuginfo, p-cpe:/a:amazon:linux:libsmbclient-devel, p-cpe:/a:amazon:linux:libsmbclient, p-cpe:/a:amazon:linux:libwbclient-debuginfo, p-cpe:/a:amazon:linux:libwbclient-devel, p-cpe:/a:amazon:linux:libwbclient, p-cpe:/a:amazon:linux:python3-samba-dc-debuginfo, p-cpe:/a:amazon:linux:python3-samba-dc, p-cpe:/a:amazon:linux:python3-samba-debuginfo, p-cpe:/a:amazon:linux:python3-samba-devel, p-cpe:/a:amazon:linux:python3-samba-test, p-cpe:/a:amazon:linux:python3-samba, p-cpe:/a:amazon:linux:samba-client-debuginfo, p-cpe:/a:amazon:linux:samba-client-libs-debuginfo, p-cpe:/a:amazon:linux:samba-client-libs, p-cpe:/a:amazon:linux:samba-client, p-cpe:/a:amazon:linux:samba-common-libs-debuginfo, p-cpe:/a:amazon:linux:samba-common-libs, p-cpe:/a:amazon:linux:samba-common-tools-debuginfo, p-cpe:/a:amazon:linux:samba-common-tools, p-cpe:/a:amazon:linux:samba-common, p-cpe:/a:amazon:linux:samba-dc-libs-debuginfo, p-cpe:/a:amazon:linux:samba-dc-libs, p-cpe:/a:amazon:linux:samba-dcerpc-debuginfo, p-cpe:/a:amazon:linux:samba-dcerpc, p-cpe:/a:amazon:linux:samba-debuginfo, p-cpe:/a:amazon:linux:samba-debugsource, p-cpe:/a:amazon:linux:samba-devel, p-cpe:/a:amazon:linux:samba-krb5-printing-debuginfo, p-cpe:/a:amazon:linux:samba-krb5-printing, p-cpe:/a:amazon:linux:samba-ldb-ldap-modules-debuginfo, p-cpe:/a:amazon:linux:samba-ldb-ldap-modules, p-cpe:/a:amazon:linux:samba-libs-debuginfo, p-cpe:/a:amazon:linux:samba-libs, p-cpe:/a:amazon:linux:samba-pidl, p-cpe:/a:amazon:linux:samba-test-debuginfo, p-cpe:/a:amazon:linux:samba-test-libs-debuginfo, p-cpe:/a:amazon:linux:samba-test-libs, p-cpe:/a:amazon:linux:samba-test, p-cpe:/a:amazon:linux:samba-tools, p-cpe:/a:amazon:linux:samba-usershares, p-cpe:/a:amazon:linux:samba-vfs-iouring-debuginfo, p-cpe:/a:amazon:linux:samba-vfs-iouring, p-cpe:/a:amazon:linux:samba-winbind-clients-debuginfo, p-cpe:/a:amazon:linux:samba-winbind-clients, p-cpe:/a:amazon:linux:samba-winbind-debuginfo, p-cpe:/a:amazon:linux:samba-winbind-krb5-locator-debuginfo, p-cpe:/a:amazon:linux:samba-winbind-krb5-locator, p-cpe:/a:amazon:linux:samba-winbind-modules-debuginfo, p-cpe:/a:amazon:linux:samba-winbind-modules, p-cpe:/a:amazon:linux:samba-winbind, p-cpe:/a:amazon:linux:samba

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

Exploit Ease: No known exploits are available

Patch Publication Date: 9/14/2026

Vulnerability Publication Date: 7/15/2026

Reference Information

CVE: CVE-2026-15779, CVE-2026-58218, CVE-2026-6949

IAVA: 2026-A-0794