CVE-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 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.
Key facts
- CVSS score
- 9.0 (v3.1)
- Severity
- CRITICAL
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H- Weakness (CWE)
- CWE-78
- EPSS score
- 1.8% (77th percentile)
- In CISA KEV
- No
- In EU EUVD
- Yes (EUVD-2026-32741)
- Published
- May 28, 2026
- NVD last modified
- October 8, 2026
- Status
- Modified
EU Vulnerability Database (EUVD)
This vulnerability is also tracked by ENISA as EUVD-2026-32741 in the EU Vulnerability Database. Last updated in EUVD on October 8, 2026.
View on the EU Vulnerability DatabaseAffected products
- redhat / enterprise linux
- redhat / enterprise linux
- redhat / enterprise linux
- redhat / openshift container platform
- samba / samba
Certified products that may be affected
8 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.
- Red Hat Enterprise Linux 9 Kernel Cryptographic API - Red Hat, Inc. - FIPS 140 5445 - active
- Red Hat Enterprise Linux 9 libgcrypt - Red Hat, Inc. - FIPS 140 5366 - active
- Red Hat Enterprise Linux 9 Kernel Cryptographic API - Red Hat, Inc. - FIPS 140 5034 - active
- Red Hat Enterprise Linux 9 NSS Cryptographic Module - Red Hat, Inc - FIPS 140 5022 - active
- Red Hat Enterprise Linux 9 gnutls - Red Hat, Inc. - FIPS 140 4846 - active
See all 8 in the Security Certifications Explorer.
References
- https://access.redhat.com/errata/RHSA-2026:22644(Issue Tracking)
- https://access.redhat.com/errata/RHSA-2026:22963(Issue Tracking)
- 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/errata/RHSA-2026:59831
- https://access.redhat.com/errata/RHSA-2026:60019
- https://access.redhat.com/errata/RHSA-2026:65839
- https://access.redhat.com/security/cve/CVE-2026-4408(Third Party Advisory)
- https://bugzilla.redhat.com/show_bug.cgi?id=2479762(Issue Tracking, Third Party Advisory)
- https://bugzilla.samba.org/show_bug.cgi?id=16034(Issue Tracking, Vendor Advisory)
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4408.json
Last updated October 10, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS
Query CVEs from your AI assistant
The CVE/NVD Explorer brain answers CVE questions directly inside Claude, ChatGPT, or any MCP assistant — always up to date, no setup. Add it once and stop pasting advisories into chat.
Add the CVE brain