Vulnerability Report

CVE-2026-4408

RCE

Title: Samba 'check password script' Remote Command Execution

RCE

Proof Of Concept

No public PoC currently indexed for CVE-2026-4408.

CWE Category CWE-78
Published Date May 28, 2026
Modified Date Jul 15, 2026
Exploit Status Not Found
Score 9.0 CVSS v3.1
Exploit Probability (EPSS)
2.50%

Vulnerability Summary

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 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.

Impacted Vendors

S
samba 1
S
sgi 1
R
redhat 1

Reference Links

https://access.redhat.com/security/cve/CVE-2026-4408 https://bugzilla.redhat.com/show_bug.cgi?id=2479762 https://bugzilla.samba.org/show_bug.cgi?id=16034
CVSS v3.1
Source Entity [email protected]
Severity CRITICAL
9.0
Attack Vector
NETWORK
Complexity
HIGH
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
CVSS v3.1
Source Entity [email protected]
Severity CRITICAL
9.8
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v3.1
Source Entity 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Severity CRITICAL
9.0
Attack Vector
NETWORK
Complexity
HIGH
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-4408 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

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Attack Vector Matrix

Access Vector NETWORK
Complexity HIGH
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected Stack

No specific products linked.