CVE-2023-4091

Dashboard / Vulnerabilities / CVE-2023-4091

CVE-2023-4091

Summary: Samba: smb clients can truncate files with read-only permissions

Details: 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://access.redhat.com/downloads/content/package-browser/, https://lists.debian.org/debian-lts-announce/2024/04/msg00015.html, https://lists.fedoraproject.org/archives/list/[email protected]/message/ZUMVALLFFDFC53JZMUWA6HPD7HUGAP5I/, https://www.samba.org/samba/security/CVE-2023-4091.html, https://access.redhat.com/errata/RHSA-2023:6209, https://access.redhat.com/errata/RHSA-2023:6744, 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-2023-4091, https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/4xxx/CVE-2023-4091.json, https://nvd.nist.gov/vuln/detail/CVE-2023-4091, https://security.netapp.com/advisory/ntap-20231124-0002/, https://bugzilla.redhat.com/show_bug.cgi?id=2241882, https://bugzilla.samba.org/show_bug.cgi?id=15439