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CRITICAL · 9.0

CVE-2026-4408

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 configu...

Vulnerability 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 Score

9.0

CRITICAL

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH

Affected Products

VendorProductVersions
RedhatOpenshift Container Platform4.0
SambaSamba>= 4.1.0, < 4.21.0
RedhatEnterprise Linux6.0

Related Weaknesses (CWE)

CWE-78

References

FAQ

What is CVE-2026-4408?

CVE-2026-4408 is a vulnerability with a CVSS score of 9.0 (CRITICAL). 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 configu...

How severe is CVE-2026-4408?

CVE-2026-4408 has been rated CRITICAL with a CVSS base score of 9.0/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-4408?

Check the references section above for vendor advisories and patch information. Affected products include: Redhat Openshift Container Platform, Samba Samba, Redhat Enterprise Linux.