CVE-2026-4408: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in Red Hat Red Hat Enterprise Linux 10
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.
AI Analysis
Technical Summary
The vulnerability CVE-2026-4408 in Samba on Red Hat Enterprise Linux 10 involves improper escaping of shell meta-characters in the 'check password script' when the %u substitution character is used. This allows a remote attacker to execute arbitrary OS commands by controlling the username passed to the script. The issue primarily affects non-standard Samba configurations where the 'check password script' feature is enabled with %u and the samba-dcerpcd service runs as a system service. Red Hat has issued security advisories and patches to fix this remote code execution vulnerability.
Potential Impact
Successful exploitation of this vulnerability allows remote attackers to execute arbitrary commands on affected systems, leading to complete compromise of confidentiality, integrity, and availability. The CVSS v3.1 base score is 9.0 (Critical), reflecting network attack vector, high complexity, no privileges required, no user interaction, and complete impact on system security properties.
Mitigation Recommendations
Red Hat has released official security updates that fix this vulnerability in Samba for Red Hat Enterprise Linux 10. Users should apply the updates as described in the Red Hat advisories RHSA-2026:22963 and RHSA-2026:22644. The vendor advisory confirms the availability of patches and recommends updating affected Samba packages to the fixed versions. Systems not using the 'check password script' with %u or not running samba-dcerpcd as a system service are less likely to be affected. Patch status is confirmed by Red Hat advisories.
CVE-2026-4408: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in Red Hat Red Hat Enterprise Linux 10
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.
CVSS v3.1
Score 9.0critical
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability CVE-2026-4408 in Samba on Red Hat Enterprise Linux 10 involves improper escaping of shell meta-characters in the 'check password script' when the %u substitution character is used. This allows a remote attacker to execute arbitrary OS commands by controlling the username passed to the script. The issue primarily affects non-standard Samba configurations where the 'check password script' feature is enabled with %u and the samba-dcerpcd service runs as a system service. Red Hat has issued security advisories and patches to fix this remote code execution vulnerability.
Potential Impact
Successful exploitation of this vulnerability allows remote attackers to execute arbitrary commands on affected systems, leading to complete compromise of confidentiality, integrity, and availability. The CVSS v3.1 base score is 9.0 (Critical), reflecting network attack vector, high complexity, no privileges required, no user interaction, and complete impact on system security properties.
Mitigation Recommendations
Red Hat has released official security updates that fix this vulnerability in Samba for Red Hat Enterprise Linux 10. Users should apply the updates as described in the Red Hat advisories RHSA-2026:22963 and RHSA-2026:22644. The vendor advisory confirms the availability of patches and recommends updating affected Samba packages to the fixed versions. Systems not using the 'check password script' with %u or not running samba-dcerpcd as a system service are less likely to be affected. Patch status is confirmed by Red Hat advisories.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- redhat
- Date Reserved
- 2026-03-18T21:40:14.142Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-4408","vendor":"Red Hat"}]
Threat ID: 6a180163e29bf47b50c5959d
Added to database: 05/28/2026, 08:48:35 UTC
Last enriched: 07/15/2026, 09:25:32 UTC
Last updated: 07/31/2026, 19:22:59 UTC
Views: 125
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