CVE-2026-4408 Samba: remote code execution in samr
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.
CVSS 3.1 detail
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:HExploitable remotely over the network, without an account and without any user action; an attacker can seriously compromise confidentiality, integrity or availability.
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- Interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Red Hat Enterprise Linux 10 | Versions not published | |
| Red Hat Enterprise Linux 6 | Versions not published | |
| Red Hat Enterprise Linux 7 | Versions not published | |
| Red Hat Enterprise Linux 8 | Versions not published | |
| Red Hat Enterprise Linux 9 | Versions not published | |
| Red Hat OpenShift Container Platform 4 | Versions not published | |
| Red Hat Enterprise Linux 9.6 Extended Update Support | Versions not published | |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | Versions not published | |
| Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | Versions not published |