Vulnerability CVE-2023-4091
Published: 2023-11-03

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.

 References:
https://www.samba.org/samba/security/CVE-2023-4091.html
https://bugzilla.samba.org/show_bug.cgi?id=15439
https://access.redhat.com/errata/RHSA-2023:6209
https://bugzilla.redhat.com/show_bug.cgi?id=2241882
https://access.redhat.com/security/cve/CVE-2023-4091
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