EUVD Vulnerability Catalog
EUVD-2026-32741
Severity: CRITICAL
Base Score: 9
CVSS Version: 3.1
Vulnerability 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 Vector Analysis
Below is the complete, human-readable breakdown of the CVSS metric string: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
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Attack Vector (AV): Network
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Attack Complexity (AC): High
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Privileges Required (PR): None
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User Interaction (UI): None
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Scope (S): Changed
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Confidentiality Impact (C): High
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Integrity Impact (I): High
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Availability Impact (A): High
Affected Vendors & Systems
Vendor
Red Hat
References & Advisory Links
- https://access.redhat.com/errata/RHSA-2026:22644
- https://access.redhat.com/errata/RHSA-2026:22963
- https://access.redhat.com/errata/RHSA-2026:25049
- https://access.redhat.com/errata/RHSA-2026:25979
- https://access.redhat.com/errata/RHSA-2026:28053
- https://access.redhat.com/errata/RHSA-2026:28054
- https://access.redhat.com/errata/RHSA-2026:28055
- https://access.redhat.com/errata/RHSA-2026:28056
- https://access.redhat.com/errata/RHSA-2026:28057
- https://access.redhat.com/errata/RHSA-2026:28058
- https://access.redhat.com/errata/RHSA-2026:28132
- https://access.redhat.com/errata/RHSA-2026:29799
- https://access.redhat.com/errata/RHSA-2026:29833
- https://access.redhat.com/errata/RHSA-2026:29863
- https://access.redhat.com/errata/RHSA-2026:56786
- https://access.redhat.com/errata/RHSA-2026:56853
- https://access.redhat.com/errata/RHSA-2026:56911
- https://access.redhat.com/errata/RHSA-2026:57483
- https://access.redhat.com/security/cve/CVE-2026-4408
- https://bugzilla.redhat.com/show_bug.cgi?id=2479762
- https://bugzilla.samba.org/show_bug.cgi?id=16034
Metadata Profile
Database Authority
European Union Agency for Cybersecurity (ENISA) EUVD
Assigner
redhat
EPSS Probability
2.5
Known Aliases
GHSA-jg8v-92xc-cx65
CVE-2026-4408
Published On
2026-05-28
Last Updated
2026-08-31