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Linux Distros Unpatched Vulnerability : CVE-2026-4408

critical Nessus Plugin ID 316852

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Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

 - A flaw was found in Samba. A remote attacker can exploit a misconfiguration in Samba file servers and classic domain controllers that use the check password script feature. If this script is configured with the %u substitution character, the client-controlled username is passed without proper escaping of shell meta-characters. This vulnerability allows an attacker to achieve remote command execution on the affected system. This issue primarily affects non-standard configurations where the check password script is used with %u and the samba-dcerpcd service is started as a system service. (CVE-2026-4408)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

See Also

https://security-tracker.debian.org/tracker/CVE-2026-4408

https://ubuntu.com/security/CVE-2026-4408

https://access.redhat.com/security/cve/cve-2026-4408

Plugin Details

Severity: Critical

ID: 316852

File Name: unpatched_CVE_2026_4408.nasl

Version: 1.9

Type: Local

Agent: unix

Family: Misc.

Published: 5/27/2026

Updated: 6/11/2026

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 8.5

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

CVSS Score Source: CVE-2026-4408

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 9

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

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

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:11.0, cpe:/o:centos:centos:7, cpe:/o:redhat:enterprise_linux:7, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, p-cpe:/a:centos:centos:samba, p-cpe:/a:centos:centos:samba-client, p-cpe:/a:centos:centos:samba-common, p-cpe:/a:centos:centos:libsmbclient, p-cpe:/a:centos:centos:libsmbclient-devel, p-cpe:/a:centos:centos:samba-winbind, p-cpe:/a:centos:centos:samba-winbind-clients, p-cpe:/a:centos:centos:samba-winbind-krb5-locator, p-cpe:/a:centos:centos:libwbclient, p-cpe:/a:centos:centos:libwbclient-devel, p-cpe:/a:centos:centos:samba-dc, p-cpe:/a:centos:centos:samba-dc-libs, p-cpe:/a:centos:centos:samba-devel, p-cpe:/a:centos:centos:samba-libs, p-cpe:/a:centos:centos:samba-pidl, p-cpe:/a:centos:centos:samba-python, p-cpe:/a:centos:centos:samba-test, p-cpe:/a:centos:centos:samba-test-devel, p-cpe:/a:centos:centos:samba-vfs-glusterfs, p-cpe:/a:centos:centos:samba-winbind-modules, p-cpe:/a:centos:centos:ctdb, p-cpe:/a:centos:centos:ctdb-devel, p-cpe:/a:centos:centos:ctdb-tests, p-cpe:/a:centos:centos:samba-client-libs, p-cpe:/a:centos:centos:samba-common-libs, p-cpe:/a:centos:centos:samba-common-tools, p-cpe:/a:centos:centos:samba-test-libs, p-cpe:/a:centos:centos:samba-krb5-printing, p-cpe:/a:centos:centos:samba-python-test, p-cpe:/a:debian:debian_linux:samba, p-cpe:/a:redhat:enterprise_linux:samba, p-cpe:/a:redhat:enterprise_linux:samba-client, p-cpe:/a:redhat:enterprise_linux:samba-common, p-cpe:/a:redhat:enterprise_linux:libsmbclient, p-cpe:/a:redhat:enterprise_linux:libsmbclient-devel, p-cpe:/a:redhat:enterprise_linux:samba-winbind, p-cpe:/a:redhat:enterprise_linux:samba-winbind-clients, p-cpe:/a:redhat:enterprise_linux:samba-winbind-krb5-locator, p-cpe:/a:redhat:enterprise_linux:ctdb, p-cpe:/a:redhat:enterprise_linux:ctdb-devel, p-cpe:/a:redhat:enterprise_linux:ctdb-tests, p-cpe:/a:redhat:enterprise_linux:libwbclient, p-cpe:/a:redhat:enterprise_linux:libwbclient-devel, p-cpe:/a:redhat:enterprise_linux:samba-client-libs, p-cpe:/a:redhat:enterprise_linux:samba-common-libs, p-cpe:/a:redhat:enterprise_linux:samba-common-tools, p-cpe:/a:redhat:enterprise_linux:samba-dc, p-cpe:/a:redhat:enterprise_linux:samba-dc-libs, p-cpe:/a:redhat:enterprise_linux:samba-devel, p-cpe:/a:redhat:enterprise_linux:samba-libs, p-cpe:/a:redhat:enterprise_linux:samba-pidl, p-cpe:/a:redhat:enterprise_linux:samba-python, p-cpe:/a:redhat:enterprise_linux:samba-test, p-cpe:/a:redhat:enterprise_linux:samba-test-devel, p-cpe:/a:redhat:enterprise_linux:samba-test-libs, p-cpe:/a:redhat:enterprise_linux:samba-vfs-glusterfs, p-cpe:/a:redhat:enterprise_linux:samba-winbind-modules, p-cpe:/a:redhat:enterprise_linux:samba-krb5-printing, p-cpe:/a:redhat:enterprise_linux:samba-python-test, p-cpe:/a:canonical:ubuntu_linux:samba, cpe:/o:canonical:ubuntu_linux:14.04:-:lts

Required KB Items: Host/cpu, Host/local_checks_enabled, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Reference Information

CVE: CVE-2026-4408