VDB

CVE-2023-4091

CVE-2023-4091 PUBLISHED CVSS 6.5 MEDIUM

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

Reported by redhat · Published November 3, 2023

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.

Fixed versions

Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.

PackageEcosystemFixed in
sambaAmazon Linux4.10.16-24.amzn2.0.4
samba-winbindAmazon Linux4.10.16-24.amzn2.0.4, 2:4.17.12-1.amzn2023.0.1
samba-dcerpcAmazon Linux2:4.17.12-1.amzn2023.0.1
libsmbclientAmazon Linux4.10.16-24.amzn2.0.4, 2:4.17.12-1.amzn2023.0.1
libnetapiAmazon Linux2:4.17.12-1.amzn2023.0.1
samba-dc-libsAmazon Linux4.10.16-24.amzn2.0.4, 2:4.17.12-1.amzn2023.0.1
libwbclientAmazon Linux4.10.16-24.amzn2.0.4, 2:4.17.12-1.amzn2023.0.1
samba-common-toolsAmazon Linux2:4.17.12-1.amzn2023.0.1
python3-samba-testAmazon Linux2:4.17.12-1.amzn2023.0.1
samba-client-libsAmazon Linux4.10.16-24.amzn2.0.4
samba-pidlAmazon Linux2:4.17.12-1.amzn2023.0.1
ctdbAmazon Linux4.10.16-24.amzn2.0.4

11 more packages have a fixed version. See every fix in Lookup.

Risk scores

CVSS 3.1
6.5
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Affected products

VendorProductVersions
Red HatRed Hat Enterprise Linux 80:4.18.6-2.el8_9
Red HatRed Hat Enterprise Linux 80:4.18.6-2.el8_9
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support0:4.15.5-13.el8_6
Red HatRed Hat Enterprise Linux 8.8 Extended Update Support0:4.17.5-4.el8_8
Red HatRed Hat Enterprise Linux 90:4.18.6-101.el9_3
Red HatRed Hat Enterprise Linux 90:4.18.6-101.el9_3
Red HatRed Hat Enterprise Linux 9.0 Extended Update Support0:4.15.5-111.el9_0
Red HatRed Hat Enterprise Linux 9.2 Extended Update Support0:4.17.5-104.el9_2
Red HatRed Hat Virtualization 4 for Red Hat Enterprise Linux 80:4.15.5-13.el8_6
Red HatRed Hat Enterprise Linux 6
Red HatRed Hat Enterprise Linux 6
Red HatRed Hat Enterprise Linux 7
Red HatRed Hat Storage 3
amazon:2samba0
amazon:2023samba-winbind0
Red HatRed Hat Storage 3
amazon:2023samba-dcerpc0
amazon:2023libsmbclient0
amazon:2023libnetapi0
amazon:2samba-dc-libs0

…and 64 more

Timeline

  • Oct 10, 2023 CVE Published
  • Nov 3, 2023 EPSS Score (30 in total, the first dated here)
  • Mar 11, 2026 Distribution Patch (10 in total, the first dated here)
  • Mar 11, 2026 Security Advisory (12 in total, the first dated here)
  • Aug 4, 2026 Coalition ESS Score

Query this with the API

The same record, from the CLI:

vulnetix vdb vuln CVE-2023-4091
vulnetix vdb fixes CVE-2023-4091

Or with curl, using the org id and key from your account page:

curl -s -H "Authorization: ApiKey ${VULNETIX_ORG_ID}:${VULNETIX_API_KEY}" \
  "https://api.vdb.vulnetix.com/v2/vuln/CVE-2023-4091/fixes/registry"

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References

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