---
id: CVE-2026-64159
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  netfs: Fix zeropoint update where i_size > remote_i_size

  Fix the update of the zero point[*] by netfs_release_folio() when there is
  uncommitted data in the pagecache b…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  netfs: Fix zeropoint update where i_size > remote_i_size

  Fix the update of the zero point[*] by netfs_release_folio() when there is
  uncommitted data in the pagecache b…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 6.10.8, < 6.11'
  - 'linux_kernel >= 6.11.1, < 7.0.11'
  - linux_kernel = 6.11
  - linux_kernel = 7.1
patched:
  - linux_kernel 7.0.11
published: '2026-07-19'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T11:17:39.663'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64159'
references:
  - url: 'https://git.kernel.org/stable/c/4543a4d737944134a1394afe797622546fbcc98a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5afc2d9b86bed2e4d9e1ba467790cbc793223f98'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5cd5207de519ef0c085f4f559adf5eefcb4c5202'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00143
epssPercentile: 0.03221
ingestedAt: '2026-10-15T11:00:41.693Z'
---

## Overview

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

netfs: Fix zeropoint update where i_size > remote_i_size

Fix the update of the zero point[*] by netfs_release_folio() when there is
uncommitted data in the pagecache beyond the folio being released but the
on-server EOF is in this folio (ie. i_size > remote_i_size).  The update
needs to limit zero_point to remote_i_size, not i_size as i_size is a local
phenomenon reflecting updates made locally to the pagecache, not stuff
written to the server.  remote_i_size tracks the server's i_size.

[*] The zero point is the file position from which we can assume that the
    server will just return zeros, so we can avoid generating reads.

Note that netfs_invalidate_folio() probably doesn't need fixing as
zero_point should be updated by setattr after truncation or fallocate.

Found with:

    fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \
        /xfstest.test/junk --replay-ops=junk.fsxops

using the following as junk.fsxops:

    truncate 0x0 0x1bbae 0x82864
    write 0x3ef2e 0xf9c8 0x1bbae
    write 0x67e05 0xcb5a 0x4e8f6
    mapread 0x57781 0x85b6 0x7495f
    copy_range 0x5d3d 0x10329 0x54fac 0x7495f
    write 0x64710 0x1c2b 0x7495f
    mapread 0x64000 0x1000 0x7495f

on cifs with the default cache option.

It shows read-gaps on folio 0x64 failing with a short read (ie. it hits
EOF) if the FMODE_READ check is commented out in netfs_perform_write():

                if (//(file->f_mode & FMODE_READ) ||
                    netfs_is_cache_enabled(ctx)) {

and no fscache.  This was initially found with the generic/522 xfstest.

## Affected

- `linux_kernel >= 6.10.8, < 6.11`
- `linux_kernel >= 6.11.1, < 7.0.11`
- `linux_kernel = 6.11`
- `linux_kernel = 7.1`

## Remediation

Upgrade past the affected range:

- `linux_kernel 7.0.11`