Samba: remote code execution in samr
Summary
| CVE | CVE-2026-4408 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-28 09:16:47 UTC |
| Updated | 2026-06-23 08:16:25 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 9.8 CRITICAL from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.018690000 probability, percentile 0.765940000 (date 2026-06-22)
Problem Types: CWE-78 | CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | [email protected] | Secondary | 9 | CRITICAL | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |
| 3.1 | CNA | CVSS | 9 | CRITICAL | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Operating System | Redhat | Enterprise Linux | 6.0 | All | All | All |
| Operating System | Redhat | Enterprise Linux | 7.0 | All | All | All |
| Operating System | Redhat | Enterprise Linux | 9.0 | All | All | All |
| Application | Redhat | Openshift Container Platform | 4.0 | All | All | All |
| Application | Samba | Samba | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Enterprise Linux 10 | unaffected 0:4.23.5-109.el10_2 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | unaffected 0:4.21.3-114.el10_0.1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | unaffected 0:4.10.16-26.el7_9.1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | unaffected 0:4.10.16-26.el7_9.1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8 | unaffected 0:4.19.4-16.el8_10 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8 | unaffected 0:4.19.4-16.el8_10 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | unaffected 0:4.13.3-12.el8_4.1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | unaffected 0:4.13.3-12.el8_4.1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | unaffected 0:4.15.5-16.el8_6.1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | unaffected 0:4.15.5-16.el8_6.1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | unaffected 0:4.17.5-7.el8_8.1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8.8 Update Services For SAP Solutions | unaffected 0:4.17.5-7.el8_8.1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9 | unaffected 0:4.23.5-10.el9_8 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9 | unaffected 0:4.23.5-10.el9_8 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9.2 Update Services For SAP Solutions | unaffected 0:4.17.5-105.el9_2.5 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9.4 Update Services For SAP Solutions | unaffected 0:4.19.4-105.el9_4.4 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | unaffected 0:4.21.3-14.el9_6.1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| CNA | Red Hat | Red Hat OpenShift Container Platform 4 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| access.redhat.com/errata/RHSA-2026:28132 | [email protected] | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:28053 | [email protected] | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:28054 | [email protected] | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:25979 | [email protected] | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:22963 | [email protected] | access.redhat.com | Issue Tracking |
| access.redhat.com/errata/RHSA-2026:28058 | [email protected] | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:22644 | [email protected] | access.redhat.com | Issue Tracking |
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | Issue Tracking, Third Party Advisory |
| access.redhat.com/errata/RHSA-2026:28055 | [email protected] | access.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-4408 | [email protected] | access.redhat.com | Third Party Advisory |
| access.redhat.com/errata/RHSA-2026:25049 | [email protected] | access.redhat.com | |
| bugzilla.samba.org/show_bug.cgi | [email protected] | bugzilla.samba.org | Issue Tracking, Vendor Advisory |
| access.redhat.com/errata/RHSA-2026:28056 | [email protected] | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:28057 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank John Walker (ZeroPath) and Ron Ben Yizhak (SafeBreach) for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-05-19T09:24:56.961Z | Reported to Red Hat. |
| CNA | 2026-05-26T00:00:00.000Z | Made public. |
Workarounds
CNA: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
There are currently no legacy QID mappings associated with this CVE.