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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 8 | — | — |
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support | — | — |
| Red Hat | Red Hat Enterprise Linux 8.8 Extended Update Support | — | — |
| Red Hat | Red Hat Enterprise Linux 9 | — | — |
| Red Hat | Red Hat Enterprise Linux 9.0 Extended Update Support | — | — |
| Red Hat | Red Hat Enterprise Linux 9.2 Extended Update Support | — | — |
| Red Hat | Red Hat Virtualization 4 for Red Hat Enterprise Linux 8 | — | — |
| Red Hat | Red Hat Enterprise Linux 6 | — | — |
| Red Hat | Red Hat Enterprise Linux 7 | — | — |
| Red Hat | Red Hat Storage 3 | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | samba | 2:4.19.1+dfsg-1 | — |
| Debian 13 | samba | 2:4.19.1+dfsg-1 | — |
| Debian 12 | samba | 2:4.17.12+dfsg-0+deb12u1 | DSA-5525-1 |
| Debian 11 | samba | 2:4.13.13+dfsg-1~deb11u6 | DSA-5647-1 |
| Debian 10 | samba | 2:4.9.5+dfsg-5+deb10u5 | DLA-3792-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | samba | 2:4.18.6+dfsg-1ubuntu2.1 | — |
| Ubuntu 22.04 LTS | samba | 2:4.15.13+dfsg-0ubuntu1.5 | USN-6425-1 |
| Ubuntu 20.04 LTS | samba | 2:4.15.13+dfsg-0ubuntu0.20.04.6 | USN-6425-1 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 18.04 LTS | samba | No fix yet | — |
| Ubuntu Pro 16.04 LTS | samba | No fix yet | — |
| Ubuntu Pro 14.04 LTS | samba | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9 | ctdb +33 | 4.18.6-101.el9_3 | RHSA-2023:6744 |
| RHEL 8 | ctdb +33 | 4.18.6-2.el8_9 | RHSA-2023:7467 |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Rhev Hypervisor 4 | samba +5 | 4.15.5-13.el8_6 | RHSA-2023:7408 |
| RHEL 9.2 EUS | ctdb +33 | 4.17.5-104.el9_2 | RHSA-2023:7371 |
| RHEL 9.0 EUS | ctdb +23 | 4.15.5-111.el9_0 | RHSA-2023:6209 |
| RHEL 8.8 EUS | ctdb +33 | 4.17.5-4.el8_8 | RHSA-2023:7464 |
| RHEL 8.6 EUS | ctdb +24 | 4.15.5-13.el8_6 | RHSA-2023:7408 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 9 | ctdb +33 | 4.18.6-101.el9_3.alma.1 | ALSA-2023:6744 |
| AlmaLinux 8 | ctdb +33 | 4.18.6-2.el8_9.alma.1 | ALSA-2023:7467 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP5 | samba | 4.17.9+git.421.abde31ca5c2-150500.3.11.1 | SUSE-SU-2023:4046-1 |
| SLES 15 SP4 | samba | 4.15.13+git.691.3d3cea0641-150400.3.31.1 | SUSE-SU-2023:4059-1 |
| SLES 15 SP3 | samba | 4.15.13+git.691.3d3cea0641-150300.3.63.1 | SUSE-SU-2023:4096-1 |
| SLES 12 SP5 | samba | 4.15.13+git.625.ac658f2f12-3.88.1 | SUSE-SU-2023:4040-1 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP3 | samba | 4.15.13+git.691.3d3cea0641-150300.3.63.1 | SUSE-SU-2023:4096-1 |
| SLES for SAP 12 SP5 | samba | 4.15.13+git.625.ac658f2f12-3.88.1 | SUSE-SU-2023:4040-1 |
| SLE Micro 5.5 | samba | 4.17.9+git.421.abde31ca5c2-150500.3.11.1 | SUSE-SU-2023:4046-1 |
| SLE Micro 5.4 | samba | 4.15.13+git.691.3d3cea0641-150400.3.31.1 | SUSE-SU-2023:4059-1 |
| SLE Micro 5.3 | samba | 4.15.13+git.691.3d3cea0641-150400.3.31.1 | SUSE-SU-2023:4059-1 |
| SLE Micro 5.2 | samba | 4.15.13+git.691.3d3cea0641-150300.3.63.1 | SUSE-SU-2023:4096-1 |
| SLE HPC 15 SP3 | samba | 4.15.13+git.691.3d3cea0641-150300.3.63.1 | SUSE-SU-2023:4096-1 |
| SUSE Manager Server 4.2 | samba | 4.15.13+git.691.3d3cea0641-150300.3.63.1 | SUSE-SU-2023:4096-1 |
| SUSE Manager Proxy 4.2 | samba | 4.15.13+git.691.3d3cea0641-150300.3.63.1 | SUSE-SU-2023:4096-1 |
| SUSE Enterprise Storage 7.1 | samba | 4.15.13+git.691.3d3cea0641-150300.3.63.1 | SUSE-SU-2023:4096-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | samba | 4.19.1+git.312.c912b3d2ef6-1.1 | openSUSE-SU-2024:13332-1 |
| openSUSE Leap 15.5 | samba | 4.17.9+git.421.abde31ca5c2-150500.3.11.1 | SUSE-SU-2023:4046-1 |
| openSUSE Leap 15.4 | samba | 4.15.13+git.691.3d3cea0641-150400.3.31.1 | SUSE-SU-2023:4059-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | samba | 4.18.8-r0 | — |
| Alpine v3.23 | samba | 4.18.8-r0 | — |
| Alpine v3.22 | samba | 4.18.8-r0 | — |
| Alpine v3.21 | samba | 4.18.8-r0 | — |
| Alpine v3.20 | samba | 4.18.8-r0 | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | samba | 4.18.8-r0 | — |
| Alpine v3.18 | samba | 4.18.8-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | samba +31 | 2:4.17.12-1.amzn2023.0.1 | ALAS2023-2023-416 |
| Amazon Linux 2 | ctdb +26 | 4.10.16-24.amzn2.0.4 | ALAS2-2023-2367 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | samba | No fix yet | — |
| Azure Linux 2 (CBL-Mariner) | samba | No fix yet | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | samba +32 | 4.18.6-101.el9_3 | ELSA-2023-6744 |
| Oracle Linux 8 | ctdb +34 | 4.18.6-2.0.1.el8_9 | ELSA-2023-7467 |
Advisories 23
- ALSA-2023:6744 Moderate: samba security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2023:7467 Moderate: samba security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2023:7464 Red Hat Security Advisory: samba security update Red Hat Security Advisories (RHSA) · Jul 28, 2026
- RHSA-2023:7467 Red Hat Security Advisory: samba security update Red Hat Security Advisories (RHSA) · Jul 28, 2026
- RHSA-2023:7408 Red Hat Security Advisory: samba security update Red Hat Security Advisories (RHSA) · Jul 28, 2026
- RHSA-2023:7371 Red Hat Security Advisory: samba security update Red Hat Security Advisories (RHSA) · Jul 28, 2026
- RHSA-2023:6744 Red Hat Security Advisory: samba security update Red Hat Security Advisories (RHSA) · Jul 28, 2026
- RHSA-2023:6209 Red Hat Security Advisory: samba security update Red Hat Security Advisories (RHSA) · Jul 28, 2026
- USN-6425-1 samba vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- DSA-5647-1 samba - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-5525-1 samba - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-3792-1 samba - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2023:4059-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:4040-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:4096-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:13332-1 ctdb-4.19.1+git.312.c912b3d2ef6-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:4046-1 Security update for samba SUSE / openSUSE Security Updates · May 2, 2025
- WID-SEC-2023-2620 Samba: Mehrere Schwachstellen BSI CERT-Bund (WID) · Apr 9, 2025
- NCSC-2025-0026 Kwetsbaarheden verholpen in Oracle JD Edwards NCSC-NL (Netherlands) · Jan 22, 2025
- ALAS2-2023-2367 Moderate: samba security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Dec 4, 2023
- ELSA-2023-7467 Moderate: samba security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 23, 2023
- ELSA-2023-6744 Moderate: samba security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Nov 16, 2023
- ALAS2023-2023-416 Important: samba security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Nov 3, 2023
References
- RHSA-2023:6209 vendor-advisory
- RHSA-2023:6744 vendor-advisory
- RHSA-2023:7371 vendor-advisory
- RHSA-2023:7408 vendor-advisory
- RHSA-2023:7464 vendor-advisory
- RHSA-2023:7467 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2023-4091 vdb-entry
- RHBZ#2241882 issue-tracking
- https://bugzilla.samba.org/show_bug.cgi?id=15439
- https://www.samba.org/samba/security/CVE-2023-4091.html