Description
A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "acl_xattr" is configured with "acl_xattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions.
Published: 2023-11-03
Score: 6.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

No analysis available yet.

Remediation

Vendor Workaround

The vulnerability is most commonly associated with the "acl_xattr" module and can be mitigated by setting: ~~~ "acl_xattr:ignore system acls = no" ~~~

Tracking

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-3792-1 samba security update
Debian DSA Debian DSA DSA-5525-1 samba security update
Debian DSA Debian DSA DSA-5647-1 samba security update
EUVD EUVD EUVD-2023-53981 A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "acl_xattr" is configured with "acl_xattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions.
Ubuntu USN Ubuntu USN USN-6425-1 Samba vulnerabilities
Ubuntu USN Ubuntu USN USN-6425-3 Samba vulnerabilities
History

Sat, 30 Aug 2025 07:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Mon, 14 Jul 2025 13:45:00 +0000

Type Values Removed Values Added
Metrics epss

{'score': 0.00476}

epss

{'score': 0.00409}


Subscriptions

Fedoraproject Fedora
Redhat Enterprise Linux Enterprise Linux Eus Rhel Eus Rhev Hypervisor Storage
Samba Samba
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2025-11-20T18:27:17.162Z

Reserved: 2023-08-02T09:43:21.439Z

Link: CVE-2023-4091

cve-icon Vulnrichment

Updated: 2024-08-02T07:17:11.687Z

cve-icon NVD

Status : Modified

Published: 2023-11-03T08:15:08.197

Modified: 2024-11-21T08:34:22.283

Link: CVE-2023-4091

cve-icon Redhat

Severity : Moderate

Publid Date: 2023-10-10T00:00:00Z

Links: CVE-2023-4091 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses