CVE-2026-4408

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.

How to fix CVE-2026-4408

To remediate CVE-2026-4408, upgrade the affected package to a fixed version below.

• —upgrade to 4.22.10-r0 or later
• —no fix listed

Is CVE-2026-4408 being exploited?

Low — EPSS is 0.4%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 4.22.10-r0
• from 0

CVSS scores

References (2)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2026-4408
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2026-4408