Command injection in Samba - CVE-2026-4408
Published: May 27, 2026
Vulnerability identifier: #VU132344
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: CVE-2026-4408
CWE-ID: CWE-77
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Samba
Affected software:
Samba
Samba
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to command injection in the Samba DCE/RPC SAMR server when invoking a check password script that uses the %u substitution character. A remote attacker can send crafted input that reaches the check password script to execute arbitrary code.
Exploitation requires samba-dcerpcd to be started as a system service on Samba file servers or classic non-AD domain controllers, and requires a configured "check password script" that uses the %u substitution character.
How to mitigate CVE-2026-4408
Install security update from vendor's website.