Is there a public exploit for CVE-2026-4408?

Yes. Proof-of-concept code for CVE-2026-4408 has been published publicly.

Is there a proof of concept for CVE-2026-4408?

Yes — 1 proof-of-concept entry is linked on this page, from public repositories and community submissions. They are listed for authorised testing only.

How severe is CVE-2026-4408?

CVE-2026-4408 scores CVSS 9 (v3.1), rated critical. EPSS puts the chance of exploitation in the next 30 days at 2.5%.

What does CVE-2026-4408 affect?

CVE-2026-4408 affects Red Hat Red Hat OpenShift Container Platform 4.16, Red Hat Enterprise Linux 10.0 Extended Update Support, Red Hat Enterprise Linux 9.6 Extended Update Support, Red Hat OpenShift Container Platform 4.13, Red Hat OpenShift Container Platform 4.18, Red Hat Enterprise Linux 8.

9.0 Critical

A flaw was found in Samba.

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.

Proof-of-concept code is published

Public PoC

Public PoCSafeBreach-Labs/ForgottenButNotGone10 stars

Signals come from Exploit-DB, Metasploit, Nuclei and published proof-of-concept repositories. Their absence means nothing was found, not that nothing exists.

Assessment

CVSS: 9 (v3.1)
Severity: Critical
EPSS: 2.5% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Public PoC
Published: 28 May 2026
Last updated: 3 November 2026
Affected: Red Hat · Red Hat Enterprise Linux 10 · Red Hat Enterprise Linux 10.0 Extended Update Support · Red Hat Enterprise Linux 7 Extended Lifecycle Support · Red Hat Enterprise Linux 8
Assigner: redhat

CVSS vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

At the source

EUVD (ENISA)

References

Community proofs of concept

No community proof of concept yet. If you have one for a published vulnerability and the right to share it, add it below — it will appear here once reviewed.

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