In the Linux kernel, the following vulnerability has been resolved:

smb: client: use kzalloc to zero-initialize security descriptor buffer

Commit 62e7dd0a39c2d ("smb: common: change the data type of num_aces
to le16") split struct smb_acl's __le32 num_aces field into __le16
num_aces and __le16 reserved. The reserved field corresponds to Sbz2
in the MS-DTYP ACL wire format, which must be zero [1].

When building an ACL descriptor in build_sec_desc(), we are using a
kmalloc()'ed descriptor buffer and writing the fields explicitly using
le16() writes now. This never writes to the 2 byte reserved field,
leaving it as uninitialized heap data.

When the reserved field happens to contain non-zero slab garbage,
Samba rejects the security descriptor with "ndr_pull_security_descriptor
failed: Range Error", causing chmod to fail with EINVAL.

Change kmalloc() to kzalloc() to ensure the entire buffer is
zero-initialized.


[1] https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-dtyp/20233ed8-a6c6-4097-aafa-dd545ed24428

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Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 29 May 2026 03:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-788

Fri, 29 May 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-909
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate


Thu, 28 May 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-788

Thu, 28 May 2026 10:15:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: smb: client: use kzalloc to zero-initialize security descriptor buffer Commit 62e7dd0a39c2d ("smb: common: change the data type of num_aces to le16") split struct smb_acl's __le32 num_aces field into __le16 num_aces and __le16 reserved. The reserved field corresponds to Sbz2 in the MS-DTYP ACL wire format, which must be zero [1]. When building an ACL descriptor in build_sec_desc(), we are using a kmalloc()'ed descriptor buffer and writing the fields explicitly using le16() writes now. This never writes to the 2 byte reserved field, leaving it as uninitialized heap data. When the reserved field happens to contain non-zero slab garbage, Samba rejects the security descriptor with "ndr_pull_security_descriptor failed: Range Error", causing chmod to fail with EINVAL. Change kmalloc() to kzalloc() to ensure the entire buffer is zero-initialized. [1] https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-dtyp/20233ed8-a6c6-4097-aafa-dd545ed24428
Title smb: client: use kzalloc to zero-initialize security descriptor buffer
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-06-14T17:57:22.559Z

Reserved: 2026-05-13T15:03:33.100Z

Link: CVE-2026-46139

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-28T10:16:29.470

Modified: 2026-05-28T13:44:01.663

Link: CVE-2026-46139

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-05-28T00:00:00Z

Links: CVE-2026-46139 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-05-29T04:45:36Z

Weaknesses