---
id: CVE-2026-89642
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  cifs: call pagecache_isize_extended() in cifs_setsize() when extending

  cifs_setsize() calls truncate_pagecache() but skips
  pagecache_isize_extended() on extension
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  cifs: call pagecache_isize_extended() in cifs_setsize() when extending

  cifs_setsize() calls truncate_pagecache() but skips
  pagecache_isize_extended() on extension.  tr…
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-201
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    e1f692b6da3e632a25d0b3a99f833bb609bae1a3
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    12bafe32f09c0d24f5096154b59c347b9c6606e0
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    c510edb9734af1c274d18f4f31a471a166bbc7e8
  - Linux 2.6.12
published: '2026-09-11'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T11:17:54.727'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89642'
references:
  - url: 'https://git.kernel.org/stable/c/12bafe32f09c0d24f5096154b59c347b9c6606e0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c510edb9734af1c274d18f4f31a471a166bbc7e8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e1f692b6da3e632a25d0b3a99f833bb609bae1a3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89642.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89642'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532207'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89642'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89642'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89642.mbox
  - url: 'https://git.kernel.org/stable/c/5463d96cd2e46064ceefcf861b028745a4f4c373'
  - url: 'https://git.kernel.org/stable/c/40c16040783abcc240bd1b453e679ea6ca30e19e'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00209
epssPercentile: 0.10966
cvssSource: vendor
ingestedAt: '2026-09-14T15:23:07.476Z'
---

## Overview

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

cifs: call pagecache_isize_extended() in cifs_setsize() when extending

cifs_setsize() calls truncate_pagecache() but skips
pagecache_isize_extended() on extension.  truncate_setsize() shows
the correct pattern:

  i_size_write(inode, newsize);
  if (newsize > oldsize)
      pagecache_isize_extended(inode, oldsize, newsize);
  truncate_pagecache(inode, newsize);

pagecache_isize_extended() zeroes the tail of the page straddling old
EOF.  Without it, dirty bytes in that region can be written back to
the server, exposing stale data in the newly extended range.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89642.json)