Samba: smb clients can truncate files with read-only permissions
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
- Nov 3, 2023
- Updated
- Jun 17, 2026
- EPSS
- 1.2% · 67th percentile
- CWE
- CWE-276
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Report tools
Action score
26
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 6.5
- CNA · redhat
- 6.5
- agree
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| samba | samba | cpe:2.3:a:samba:samba |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| redhat | storage | cpe:2.3:a:redhat:storage |
| redhat | enterprise linux | cpe:2.3:o:redhat:enterprise_linux |
| redhat | enterprise linux eus | cpe:2.3:o:redhat:enterprise_linux_eus |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- fedoraproject fedora39
- redhat enterprise linux8.0
- redhat enterprise linux eus9.0
- redhat storage3.0
- samba samba4.18.0 and later · before 4.18.8
- samba samba4.19.0 and later · before 4.19.1
- samba sambabefore 4.17.12
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
Red Hat Red Hat Enterprise Linux 6
- all versionsunknown
- all versionsunknown
Red Hat Red Hat Enterprise Linux 7
- all versionsunknown
Red Hat Red Hat Enterprise Linux 8
- 0:4.18.6-2.el8_9 and laternot affected · rpm
- 0:4.18.6-2.el8_9 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support
- 0:4.15.5-13.el8_6 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 8.8 Extended Update Support
- 0:4.17.5-4.el8_8 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 9
- 0:4.18.6-101.el9_3 and laternot affected · rpm
- 0:4.18.6-101.el9_3 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 9.0 Extended Update Support
- 0:4.15.5-111.el9_0 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 9.2 Extended Update Support
- 0:4.17.5-104.el9_2 and laternot affected · rpm
Red Hat Red Hat Storage 3
- all versionsunknown
Red Hat Red Hat Virtualization 4 for Red Hat Enterprise Linux 8
- 0:4.15.5-13.el8_6 and laternot affected · rpm
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | ctdb | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | libnetapi | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | libnetapi-devel | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | libsmbclient | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | libsmbclient-devel | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | libwbclient | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | libwbclient-devel | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | python3-samba | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | python3-samba-dc | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | python3-samba-devel | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | python3-samba-test | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | samba | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | samba-client | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | samba-client-libs | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | samba-common | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | samba-common-libs | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | samba-common-tools | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | samba-dc-libs | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | samba-dcerpc | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | samba-devel | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | samba-krb5-printing | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | samba-ldb-ldap-modules | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | samba-libs | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
| AlmaLinux:8 | samba-pidl | before 4.18.6-2.el8_9.alma.1 | 4.18.6-2.el8_9.alma.1 |
+96
Same product
samba: all recordsOther highest-scoring records for the same primary product.
- CVE-2017-7494Samba since version 3.5.0 and before 4.6.4, 4.5.10 and 4.4.14 is vulnerable to remote code execution vulnerability, allowing a malicious cliKEV99Now
- CVE-2015-0240The Netlogon server implementation in smbd in Samba 3.5.x and 3.6.x before 3.6.25, 4.0.x before 4.0.25, 4.1.x before 4.1.17, and 4.2.x befor66This week
- CVE-2003-0085Buffer overflow in the SMB/CIFS packet fragment re-assembly code for SMB daemon (smbd) in Samba before 2.2.8, and Samba-TNG before 0.3.1, al66This week
- CVE-2003-0201Buffer overflow in the call_trans2open function in trans2.c for Samba 2.2.x before 2.2.8a, 2.0.10 and earlier 2.0.x versions, and Samba-TNG 65This week
- CVE-2007-2446Multiple heap-based buffer overflows in the NDR parsing in smbd in Samba 3.0.0 through 3.0.25rc3 allow remote attackers to execute arbitrary63This week
- CVE-2012-1182The RPC code generator in Samba 3.x before 3.4.16, 3.5.x before 3.5.14, and 3.6.x before 3.6.4 does not implement validation of an array len62This week
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| almalinux:ctdb | 4.18.6-101.el9_3.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libnetapi | 4.18.6-101.el9_3.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libnetapi-devel | 4.18.6-101.el9_3.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libsmbclient | 4.18.6-101.el9_3.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libsmbclient-devel | 4.18.6-101.el9_3.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libwbclient | 4.18.6-101.el9_3.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libwbclient-devel | 4.18.6-101.el9_3.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:python3-samba | 4.18.6-101.el9_3.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:python3-samba-dc | 4.18.6-101.el9_3.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:python3-samba-devel | 4.18.6-101.el9_3.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:python3-samba-test | 4.18.6-101.el9_3.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:samba | 4.18.6-101.el9_3.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| alpine:samba | 4.18.8-r0 · Alpine:v3.18 | Package registry (OSV) |
| debian:samba | 2:4.17.12+dfsg-0+deb12u1 · Debian:12 | Package registry (OSV) |
| opensuse:samba | 4.17.9+git.421.abde31ca5c2-150500.3.11.1 · openSUSE:Leap 15.5 | Package registry (OSV) |
| red hat:ctdb-debuginfo | 0:4.15.5-111.el9_0 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:libsmbclient-debuginfo | 0:4.15.5-111.el9_0 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:libwbclient-debuginfo | 0:4.15.5-111.el9_0 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:python3-samba-debuginfo | 0:4.15.5-111.el9_0 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:samba-client | 0:4.15.5-111.el9_0 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:samba-client-debuginfo | 0:4.15.5-111.el9_0 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:samba-client-libs-debuginfo | 0:4.15.5-111.el9_0 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:samba-common-libs-debuginfo | 0:4.15.5-111.el9_0 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:samba-common-tools-debuginfo | 0:4.15.5-111.el9_0 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:samba-debuginfo | 0:4.15.5-111.el9_0 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:samba-debugsource | 0:4.15.5-111.el9_0 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:samba-krb5-printing | 0:4.15.5-111.el9_0 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| suse:samba | 4.15.13+git.625.ac658f2f12-3.88.1 · SUSE:Linux Enterprise High Availability Extension 12 SP5 | Package registry (OSV) |
| suse:samba | 4.17.9+git.421.abde31ca5c2-150500.3.11.1 · SUSE:Linux Enterprise Micro 5.5 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2022-0336431 days apartThe Samba AD DC includes checks when adding service principals names (SPNs) to an account to ensure that SPNs do not alias with those alread35Monitor
- CVE-2022-32743428 days apartSamba does not validate the Validated-DNS-Host-Name right for the dNSHostName attribute which could permit unprivileged users to write it.30Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- high · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- High
- Availability impact
- None
Weakness class (CWE)
CWE-276 · Incorrect Default PermissionsCVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- access.redhat.com/errata/RHSA-2023:7464
- access.redhat.com/errata/RHSA-2023:7467
- access.redhat.com/errata/RHSA-2023:6209
- access.redhat.com/errata/RHSA-2023:6744
- access.redhat.com/errata/RHSA-2023:7371
- access.redhat.com/errata/RHSA-2023:7408
- access.redhat.com/security/cve/CVE-2023-4091
- bugzilla.redhat.com/show_bug.cgi?id=2241882
- bugzilla.samba.org/show_bug.cgi?id=15439
- www.samba.org/samba/security/CVE-2023-4091.html
- lists.debian.org/debian-lts-announce/2024/04/msg00015.html
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZUMVALLFFDFC53JZMUWA6HPD7HUGAP5I/
- security.netapp.com/advisory/ntap-20231124-0002/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.