CVE-2026-4408

Samba: remote code execution in samr

Published May 28, 2026 CVSS 3.1 · 9 Critical EPSS 46.9% KEV · Not listed
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.

Remediation

Vendor Workaround

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4692-1 samba security update
Debian DSA Debian DSA DSA-6297-1 samba security update
Ubuntu USN Ubuntu USN USN-8306-1 Samba vulnerabilities
History
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:6 cpe:/o:redhat:rhel_els:6
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4.17::el9
References
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4.14::el9
cpe:/a:redhat:openshift:4.15::el9
cpe:/a:redhat:openshift:4.16::el9
References
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4.19::el9
References
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4 cpe:/a:redhat:openshift:4.21::el9
References
Type Values Removed Values Added
First Time appeared Redhat rhel Els
CPEs cpe:/o:redhat:enterprise_linux:7 cpe:/a:redhat:rhel_e4s:9.4::appstream
cpe:/a:redhat:rhel_e4s:9.4::resilientstorage
cpe:/o:redhat:enterprise_linux:7::server
cpe:/o:redhat:rhel_e4s:9.4::baseos
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Els
References
Type Values Removed Values Added
First Time appeared Redhat enterprise Linux Eus
Redhat rhel E4s
Redhat rhel Tus
CPEs cpe:/a:redhat:rhel_e4s:8.8::appstream
cpe:/a:redhat:rhel_e4s:9.2::appstream
cpe:/a:redhat:rhel_e4s:9.2::resilientstorage
cpe:/a:redhat:rhel_tus:8.8::appstream
cpe:/o:redhat:enterprise_linux_eus:10.0
cpe:/o:redhat:rhel_e4s:8.8::baseos
cpe:/o:redhat:rhel_e4s:9.2::baseos
cpe:/o:redhat:rhel_tus:8.8::baseos
Vendors & Products Redhat enterprise Linux Eus
Redhat rhel E4s
Redhat rhel Tus
References
Type Values Removed Values Added
First Time appeared Redhat rhel Aus
Redhat rhel Eus Long Life
CPEs cpe:/a:redhat:rhel_aus:8.6::appstream
cpe:/a:redhat:rhel_eus_long_life:8.6::appstream
cpe:/o:redhat:rhel_aus:8.4::baseos
cpe:/o:redhat:rhel_aus:8.6::baseos
cpe:/o:redhat:rhel_eus_long_life:8.4::baseos
cpe:/o:redhat:rhel_eus_long_life:8.6::baseos
Vendors & Products Redhat rhel Aus
Redhat rhel Eus Long Life
References
Type Values Removed Values Added
First Time appeared Redhat rhel Eus
CPEs cpe:/a:redhat:rhel_eus:9.6::appstream
cpe:/a:redhat:rhel_eus:9.6::crb
cpe:/a:redhat:rhel_eus:9.6::resilientstorage
cpe:/o:redhat:rhel_eus:9.6::baseos
Vendors & Products Redhat rhel Eus
References
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:9 cpe:/a:redhat:enterprise_linux:9::appstream
cpe:/a:redhat:enterprise_linux:9::crb
cpe:/a:redhat:enterprise_linux:9::resilientstorage
cpe:/o:redhat:enterprise_linux:9::baseos
References
Type Values Removed Values Added
CPEs cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*
cpe:2.3:a:samba:samba:*:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10 cpe:/o:redhat:enterprise_linux:10.2
References
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:8 cpe:/a:redhat:enterprise_linux:8::appstream
cpe:/a:redhat:enterprise_linux:8::crb
cpe:/o:redhat:enterprise_linux:8::baseos
References
Type Values Removed Values Added
First Time appeared Redhat openshift Container Platform
Samba
Samba samba
Vendors & Products Redhat openshift Container Platform
Samba
Samba samba
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Samba: remote code execution in samr
First Time appeared Redhat
Redhat enterprise Linux
Redhat openshift
Weaknesses CWE-78
CPEs cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat openshift
References
Metrics cvssV3_1

{'score': 9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H'}