---
id: CVE-2026-64138
title: 'ksmbd: validate SID in parent security descriptor during ACL inheritance'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ksmbd: validate SID in parent security descriptor during ACL inheritance

  Introduce smb_validate_ntsd_sid() helper to safely validate Owner SID
  and Group SID inside the…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <
    8efbea0253b7fa2d1960cab0fed36544ca0b41ab
  - >-
    Linux >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <
    f0e5c9c663badc9982e6941322eef1cb17de0f11
  - >-
    Linux >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <
    18d8db24b0a5b7be4829238dd4022236df02d421
  - >-
    Linux >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <
    1c9d0646a9959752f11ca1080dc1ff26bd1756cb
  - >-
    Linux >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <
    69f030cf95488ae1186c72ac8c66fd279664ea7f
  - Linux 5.15
published: '2026-07-19'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T12:43:05.753Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-64138'
references:
  - url: 'https://git.kernel.org/stable/c/8efbea0253b7fa2d1960cab0fed36544ca0b41ab'
  - url: 'https://git.kernel.org/stable/c/f0e5c9c663badc9982e6941322eef1cb17de0f11'
  - url: 'https://git.kernel.org/stable/c/18d8db24b0a5b7be4829238dd4022236df02d421'
  - url: 'https://git.kernel.org/stable/c/1c9d0646a9959752f11ca1080dc1ff26bd1756cb'
  - url: 'https://git.kernel.org/stable/c/69f030cf95488ae1186c72ac8c66fd279664ea7f'
tags:
  - cve.org
epss: 0.00415
epssPercentile: 0.34433
ingestedAt: '2026-10-21T12:48:53.610Z'
---

## Overview

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

ksmbd: validate SID in parent security descriptor during ACL inheritance

Introduce smb_validate_ntsd_sid() helper to safely validate Owner SID
and Group SID inside the NT Security Descriptor (smb_ntsd) retrieved
from the parent directory.

## Affected

- `Linux >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < 8efbea0253b7fa2d1960cab0fed36544ca0b41ab`
- `Linux >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < f0e5c9c663badc9982e6941322eef1cb17de0f11`
- `Linux >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < 18d8db24b0a5b7be4829238dd4022236df02d421`
- `Linux >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < 1c9d0646a9959752f11ca1080dc1ff26bd1756cb`
- `Linux >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < 69f030cf95488ae1186c72ac8c66fd279664ea7f`
- `Linux 5.15`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.