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Vulnerabilities
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CVE-2023-4091

Updated on 03 Nov 2023

Severity

6.5 Medium severity

Details

CVSS score
6.5
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
CWE ID
Links
NISTCIRCLRHELUbuntu

Overview

About vulnerability

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.

Details

Affected product:
AlmaLinux 9.2 ESU , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CloudLinux 6 ELS , Debian 10 ELS , Oracle Linux 6 ELS , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS
Affected packages:
samba @ 4.17.5 (+9 more)
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.

Fixes