CVE-2026-4408

Medium

Elevated severity or exploit probability.

CVSS base

9.0 CRITICAL

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS — probability of exploitation (30 days)

2.5%

84.0th percentile

CISA KEV

Not listed

Weakness / dates

CWE-78

Published 2026-05-28 · modified 2026-09-18

CVSS breakdown

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Attack Vector	N	Network
Attack Complexity	H	High
Privileges Required	N	None
User Interaction	N	None
Scope	C	Changed
Confidentiality	H	High
Integrity	H	High
Availability	H	High

Timeline

2026-05-28 — Published (NVD)
2026-09-18 — Last modified (NVD)

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.

Affected

redhat samba

References

Official: NVD · CVE.org