---
id: CVE-2026-43350
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  smb: client: require a full NFS mode SID before reading mode bits

  parse_dacl() treats an ACE SID matching sid_unix_NFS_mode as an NFS
  mode SID and reads sid.sub_auth[2…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  smb: client: require a full NFS mode SID before reading mode bits

  parse_dacl() treats an ACE SID matching sid_unix_NFS_mode as an NFS
  mode SID and reads sid.sub_auth[2…
severity: high
cvss: 7.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H'
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.4, < 6.6.136'
  - 'linux_kernel >= 6.7, < 6.12.84'
  - 'linux_kernel >= 6.13, < 6.18.25'
  - 'linux_kernel >= 6.19, < 7.0.2'
patched:
  - linux_kernel 7.0.2
published: '2026-05-08'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:19:33.493'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-43350'
references:
  - url: 'https://git.kernel.org/stable/c/1592a6cd6f653f2d24572a6976c7a775b19f4940'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/23b54d6cc3ef30a51d984dc74364f24039ae2ecb'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2757ad3e4b6f9e0fed4c7739594e702abc5cab21'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/38a69f08ee82c450d3e4168707fff2e317dc3ff7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8bd4cad3f458d11650d51c2d24b03fb1770ae6cc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b53b8e98c23310294fc45fc686db5ee860311896'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c8eef12af1cc73031639ea7cf16e0b10e2536b0b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f8488c07bea2431ee12a6067d736578064fa46b4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-784472.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00224
epssPercentile: 0.12082
ingestedAt: '2026-10-15T03:30:12.874Z'
---

## Overview

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

smb: client: require a full NFS mode SID before reading mode bits

parse_dacl() treats an ACE SID matching sid_unix_NFS_mode as an NFS
mode SID and reads sid.sub_auth[2] to recover the mode bits.

That assumes the ACE carries three subauthorities, but compare_sids()
only compares min(a, b) subauthorities.  A malicious server can return
an ACE with num_subauth = 2 and sub_auth[] = {88, 3}, which still
matches sid_unix_NFS_mode and then drives the sub_auth[2] read four
bytes past the end of the ACE.

Require num_subauth >= 3 before treating the ACE as an NFS mode SID.
This keeps the fix local to the special-SID mode path without changing
compare_sids() semantics for the rest of cifsacl.

## Affected

- `linux_kernel >= 5.4, < 6.6.136`
- `linux_kernel >= 6.7, < 6.12.84`
- `linux_kernel >= 6.13, < 6.18.25`
- `linux_kernel >= 6.19, < 7.0.2`

## Remediation

Upgrade past the affected range:

- `linux_kernel 7.0.2`