CVE-2023-4091
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".
Does this matter?
Lower severity and a low EPSS score (1.17%). Track it; it rarely justifies an emergency change on its own.
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 3.1
- 6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
- EPSS
- 1.17% probability · 66th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-276
- Affected
- samba/samba · fedoraproject/fedora · redhat/storage · redhat/enterprise linux · redhat/enterprise linux eus
- Source
- secalert@redhat.com
References
- https://access.redhat.com/errata/RHSA-2023:6209Third Party Advisory
- https://access.redhat.com/errata/RHSA-2023:6744Third Party Advisory
- 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-2023-4091Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2241882Issue Tracking
- https://bugzilla.samba.org/show_bug.cgi?id=15439Issue Tracking
- https://www.samba.org/samba/security/CVE-2023-4091.htmlVendor Advisory
- https://access.redhat.com/errata/RHSA-2023:6209Third Party Advisory
- https://access.redhat.com/errata/RHSA-2023:6744Third Party Advisory
- 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-2023-4091Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2241882Issue Tracking
- https://bugzilla.samba.org/show_bug.cgi?id=15439Issue Tracking
- 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/
- https://www.samba.org/samba/security/CVE-2023-4091.htmlVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.