OS Command Injection Affecting samba package, versions <2:4.15.13+dfsg-0ubuntu0.20.04.8+esm2


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
2.5% (83rd percentile)

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  • Snyk IDSNYK-UBUNTU2004-SAMBA-16877534
  • published10 Jun 2026
  • disclosed28 May 2026

Introduced: 28 May 2026

CVE-2026-4408  (opens in a new tab)
CWE-78  (opens in a new tab)

How to fix?

Upgrade Ubuntu:20.04 samba to version 2:4.15.13+dfsg-0ubuntu0.20.04.8+esm2 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream samba package and not the samba package as distributed by Ubuntu. See How to fix? for Ubuntu:20.04 relevant fixed versions and status.

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 Base Scores

version 3.1