VULNpocalypse

CVE-2026-4408: Samba: remote code execution in samr

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-11 15:49 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

What it is

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.

Description quoted from the CVE record (assigned by redhat, published 2026-05-28).

Weakness: Improper Neutralization of Special Elements used in an OS Command; Improper Neutralization of Special Elements used in an OS Command (‘OS Command Injection’)

How it can be exploited

Exploitable over the network with high attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

CISA assessment (SSVC): CISA has no evidence of exploitation. Automatable: no. Technical impact: total.

Public exploit evidence (Exploit Observer)

Exploit Observer found 1 research write-up naming this CVE.

See all 12 references on Exploit Observer

Live scores

EPSS
0.469
likely to be attacked soon
VEDAS
0.271
little exploit evidence
On CISA KEV
Not listed
Detection rule
No public rule yet

Who is affected

ProductAffectedNot affected
Red Hat Enterprise Linux 10 (samba)Not stated0:4.23.5-109.el10_2 is not affected (up to *)
Red Hat Enterprise Linux 10.0 Extended Update Support (samba)Not stated0:4.21.3-114.el10_0.1 is not affected (up to *)
Red Hat Enterprise Linux 7 Extended Lifecycle Support (samba)Not stated0:4.10.16-26.el7_9.1 is not affected (up to *)
Red Hat Enterprise Linux 7 Extended Lifecycle Support (samba)Not stated0:4.10.16-26.el7_9.1 is not affected (up to *)
Red Hat Enterprise Linux 8 (samba)Not stated0:4.19.4-16.el8_10 is not affected (up to *)
Red Hat Enterprise Linux 8 (samba)Not stated0:4.19.4-16.el8_10 is not affected (up to *)
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (samba)Not stated0:4.13.3-12.el8_4.1 is not affected (up to *)
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (samba)Not stated0:4.13.3-12.el8_4.1 is not affected (up to *)
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (samba)Not stated0:4.15.5-16.el8_6.1 is not affected (up to *)
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On (samba)Not stated0:4.15.5-16.el8_6.1 is not affected (up to *)
Red Hat Enterprise Linux 8.8 Telecommunications Update Service (samba)Not stated0:4.17.5-7.el8_8.1 is not affected (up to *)
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (samba)Not stated0:4.17.5-7.el8_8.1 is not affected (up to *)
Red Hat Enterprise Linux 9 (samba)Not stated0:4.23.5-10.el9_8 is not affected (up to *)
Red Hat Enterprise Linux 9 (samba)Not stated0:4.23.5-10.el9_8 is not affected (up to *)
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (samba)Not stated0:4.17.5-105.el9_2.5 is not affected (up to *)
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions (samba)Not stated0:4.19.4-105.el9_4.4 is not affected (up to *)
Red Hat Enterprise Linux 9.6 Extended Update Support (samba)Not stated0:4.21.3-14.el9_6.1 is not affected (up to *)
Red Hat OpenShift Container Platform 4.12 (openshift/ose-rhel-coreos-8)Not stated412.86.202608241157-0 is not affected (up to *)
Red Hat OpenShift Container Platform 4.13 (openshift/ose-rhel-coreos-9)Not stated413.92.202609080414-0 is not affected (up to *)
Red Hat OpenShift Container Platform 4.14 (openshift/ose-rhel-coreos-9)Not stated414.92.202608172040-0 is not affected (up to *)

9 more products are listed in the CVE record.

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

How to fix it

Vendor guidance:

13 more

How to detect it

There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.

References

Vendor advisories and patches

9 more

Technical analysis and advisories

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.

Supporting partners

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