---
id: CVE-2026-64395
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ksmbd: require source read access for duplicate extents

  FSCTL_DUPLICATE_EXTENTS_TO_FILE passes the source file directly to
  vfs_clone_file_range() or vfs_copy_file_rang…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ksmbd: require source read access for duplicate extents

  FSCTL_DUPLICATE_EXTENTS_TO_FILE passes the source file directly to
  vfs_clone_file_range() or vfs_copy_file_rang…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.15, < 6.1.178'
  - 'linux_kernel >= 6.2, < 6.6.145'
  - 'linux_kernel >= 6.7, < 6.12.96'
  - 'linux_kernel >= 6.13, < 6.18.39'
  - 'linux_kernel >= 6.19, < 7.1.4'
patched:
  - linux_kernel 7.1.4
published: '2026-07-25'
updated: '2026-09-04'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64395'
references:
  - url: 'https://git.kernel.org/stable/c/2d2ab6983620c2d60ce7db72133984ca3873b929'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/67bdad9cf01b25030e3bf00bbce6c309319d6663'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a10942af27832c2761d020863a46e79bebe0567d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b0d4d5cb846a1ddb7aaab9adfb5986e4540e6e5f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cedff600f1642aa982178503552f0d007bc829c8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/db231af842868268839f9f9619c68cb27830d8be'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00553
epssPercentile: 0.43976
ingestedAt: '2026-09-05T13:39:57.649Z'
---

## Overview

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

ksmbd: require source read access for duplicate extents

FSCTL_DUPLICATE_EXTENTS_TO_FILE passes the source file directly to
vfs_clone_file_range() or vfs_copy_file_range() without checking the SMB
access mask granted to the source handle. A handle opened with attribute
access can consequently be used to copy file contents into an
attacker-readable destination.

Require FILE_READ_DATA on the source handle before either VFS operation,
matching other ksmbd data-copy paths.

## Affected

- `linux_kernel >= 5.15, < 6.1.178`
- `linux_kernel >= 6.2, < 6.6.145`
- `linux_kernel >= 6.7, < 6.12.96`
- `linux_kernel >= 6.13, < 6.18.39`
- `linux_kernel >= 6.19, < 7.1.4`

## Remediation

Upgrade past the affected range:

- `linux_kernel 7.1.4`