Vulnerability · CVE-2026-4408
A flaw was found in Samba.
Published May 28, 2026 · corrected/updated Oct 8, 2026 · redhat openshift container platform · evidence confidence medium
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.
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2026-4408 is a critical public vulnerability record for redhat openshift container platform. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether redhat openshift container platform is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: redhat/enterprise linux (6.0); redhat/enterprise linux (7.0); redhat/enterprise linux (9.0); redhat/openshift container platform (4.0). Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: CVSS 9.8, EPSS 1.8%. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-78. Sources contributing to this record: epss, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.
Patch and remediation
No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Technology hubs
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
May 28, 2026 · NIST NVD
Detected
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 execu
Oct 8, 2026 · NIST NVD
Updated
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 execu
Affected
- cpe redhat/enterprise linux6.0
- cpe redhat/enterprise linux7.0
- cpe redhat/enterprise linux9.0
- cpe redhat/openshift container platform4.0
- cpe samba/sambaversion unspecified
Sources
- FIRST EPSSExploitation probabilityCVE-2026-4408
30-day exploitation probability 1.8%
first.org - NIST NVDVulnerability recordCVE-2026-4408
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
nvd.nist.gov