Vulnerability 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 Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Samba | Samba | < 4.17.12 |
| Fedoraproject | Fedora | 39 |
| Redhat | Storage | 3.0 |
| Redhat | Enterprise Linux | 8.0 |
| Redhat | Enterprise Linux Eus | 9.0 |
Related Weaknesses (CWE)
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
FAQ
What is CVE-2023-4091?
CVE-2023-4091 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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...
How severe is CVE-2023-4091?
CVE-2023-4091 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2023-4091?
Check the references section above for vendor advisories and patch information. Affected products include: Samba Samba, Fedoraproject Fedora, Redhat Storage, Redhat Enterprise Linux, Redhat Enterprise Linux Eus.