CVE-2023-4091
moderate-risk
Published 2023-11-03
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.
Do I need to act?
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0.48% chance of exploitation
EPSS score — low exploit probability
-
Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
6
CVSS 6.5/10
Medium
NETWORK
/ LOW complexity
Affected Products (5)
Affected Vendors
References (23)
Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:6209
Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:6744
Third Party Advisory
https://access.redhat.com/security/cve/CVE-2023-4091
Issue Tracking
https://bugzilla.redhat.com/show_bug.cgi?id=2241882
Issue Tracking
https://bugzilla.samba.org/show_bug.cgi?id=15439
Vendor Advisory
https://www.samba.org/samba/security/CVE-2023-4091.html
Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:6209
Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:6744
Third Party Advisory
https://access.redhat.com/security/cve/CVE-2023-4091
Issue Tracking
https://bugzilla.redhat.com/show_bug.cgi?id=2241882
Issue Tracking
https://bugzilla.samba.org/show_bug.cgi?id=15439
and 3 more references
38
/ 100
moderate-risk
Severity
24/34 · High
Exploitability
2/34 · Minimal
Exposure
12/34 · Low