CVE-2026-4408

critical

Published 2026-05-28 · Modified 2026-05-29

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CVSS v3

9.0

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

CVSS v4 NEW

—

not yet in upstream

VIR risk

9.0

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.

Predictions

Exploit likelihood

93%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

OS impact

OS	Version	Status	Fixed in
sles		affected
debian	bookworm	fixed	`2:4.17.12+dfsg-0+deb12u4`
debian	bullseye	affected
debian	sid	fixed	`2:4.24.3+dfsg-1`
debian	trixie	fixed	`2:4.22.8+dfsg-0+deb13u2`
debian	forky	fixed	`2:4.24.3+dfsg-1`

References

CWEs

CWE-78

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.