CVE-2023-4091

Advisory lineage Upstream: 0 Downstream: 19
Modified
Published: 03 Nov 2023, 07:56
Last modified:20 Nov 2025, 18:27

Vulnerability Summary

Overall Risk (default)
medium
26/100
CVSS Score
6.5 MEDIUM
v3.1 (cve.org)
EPSS Score
0.44% LOW
0% probability -0.04%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

03 Nov 2023, 07:56
Published
Vulnerability first disclosed
20 Nov 2025, 18:27
Last Modified
Vulnerability information updated

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.

CVSS Metrics

  • v3.1•MEDIUM•Score: 6.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

EPSS Trends

Current EPSS score: 0.44%• Percentile: 63%

Techniques & Countermeasures

  • CWE-276•Incorrect Default Permissions

    During installation, installed file permissions are set to allow anyone to modify those files.

Affected Systems

  • fedoraproject•fedora

    39

  • redhat•enterprise_linux

    8.0

  • redhat•enterprise_linux_eus

    9.0

  • redhat•storage

    3.0

  • samba•samba

    < 4.17.12 | ≥ 4.18.0, < 4.18.8 | ≥ 4.19.0, < 4.19.1

References (13)