CVE-2023-4091
Samba: smb clients can truncate files with read-only permissions
At a glance
- Severity
- MEDIUM 6.5
- EPSS
- EPSS 1.33 % · percentile 71 (2026-10-27)
- State
- PUBLISHED
- Published
- Updated
- Assigner
- redhat
- NVD status
- Modified
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.
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N | redhat |
| CVSS 3.1 | MEDIUM 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N | NVD · secalert@redhat.com (Secondary) |
| CVSS 3.1 | MEDIUM 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N | NVD · nvd@nist.gov (Primary) |
Weaknesses (CWE)
European references
- ENISA EUVD · EUVD-2023-53981
- GCVE · GCVE-0-2023-4091
CERT-FR advisories
- CERTFR-2025-AVI-0969 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2025-AVI-0309 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2024-AVI-0506 — Multiples vulnérabilités dans Juniper Secure Analytics · cert.ssi.gouv.fr
- CERTFR-2024-AVI-0423 — Multiples vulnérabilités dans les produits NetApp · cert.ssi.gouv.fr
- CERTFR-2024-AVI-0305 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2024-AVI-0262 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2023-AVI-1011 — Multiples vulnérabilités dans les produits Qnap · cert.ssi.gouv.fr
- CERTFR-2023-AVI-0831 — Multiples vulnérabilités dans Samba · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:samba:samba:*:*:*:*:*:*:*:*< 4.17.12cpe:2.3:a:samba:samba:*:*:*:*:*:*:*:*≥ 4.18.0 < 4.18.8cpe:2.3:a:samba:samba:*:*:*:*:*:*:*:*≥ 4.19.0 < 4.19.1cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*cpe:2.3:a:redhat:storage:3.0:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_eus:9.0:*:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| Red Hat · Red Hat Enterprise Linux 8 | unaffected 0:4.18.6-2.el8_9 < * |
| Red Hat · Red Hat Enterprise Linux 8 | unaffected 0:4.18.6-2.el8_9 < * |
| Red Hat · Red Hat Enterprise Linux 8.6 Extended Update Support | unaffected 0:4.15.5-13.el8_6 < * |
| Red Hat · Red Hat Enterprise Linux 8.8 Extended Update Support | unaffected 0:4.17.5-4.el8_8 < * |
| Red Hat · Red Hat Enterprise Linux 9 | unaffected 0:4.18.6-101.el9_3 < * |
| Red Hat · Red Hat Enterprise Linux 9 | unaffected 0:4.18.6-101.el9_3 < * |
| Red Hat · Red Hat Enterprise Linux 9.0 Extended Update Support | unaffected 0:4.15.5-111.el9_0 < * |
| Red Hat · Red Hat Enterprise Linux 9.2 Extended Update Support | unaffected 0:4.17.5-104.el9_2 < * |
| Red Hat · Red Hat Virtualization 4 for Red Hat Enterprise Linux 8 | unaffected 0:4.15.5-13.el8_6 < * |
| Red Hat · Red Hat Enterprise Linux 6 | |
| Red Hat · Red Hat Enterprise Linux 6 | |
| Red Hat · Red Hat Enterprise Linux 7 | |
| Red Hat · Red Hat Storage 3 |
References
- https://access.redhat.com/errata/RHSA-2023:6209
- https://access.redhat.com/errata/RHSA-2023:6744
- https://access.redhat.com/errata/RHSA-2023:7371
- https://access.redhat.com/errata/RHSA-2023:7408
- https://access.redhat.com/errata/RHSA-2023:7464
- https://access.redhat.com/errata/RHSA-2023:7467
- https://access.redhat.com/security/cve/CVE-2023-4091
- https://bugzilla.redhat.com/show_bug.cgi?id=2241882
- https://bugzilla.samba.org/show_bug.cgi?id=15439
- https://www.samba.org/samba/security/CVE-2023-4091.html
- https://lists.debian.org/debian-lts-announce/2024/04/msg00015.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZUMVALLFFDFC53JZMUWA6HPD7HUGAP5I/
- https://security.netapp.com/advisory/ntap-20231124-0002/
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |