---
id: CVE-2026-93235
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  f2fs: fix to zero post-EOF data when extending file size

  generic/794  4s ..
summary: >-
  In the Linux kernel, the following vulnerability has been resolved:


  f2fs: fix to zero post-EOF data when extending file size


  generic/794  4s ... - output mismatch (see
  /share/git/fstests/results//generic/794.out.bad)
      --- tests/gene…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    6882d458d2e403f6ba7b45542dd31a6b7531eb2e
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    32c7f11a24268ba8d3bb50ea7f54d33f698cd253
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    91ec55ddc097ccddd25ffb95a3d079b2ef362372
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    c42608c09b6b5d5967bf211c255914c068c2cde1
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    5eced87b7d19dbc76ebdddaf322046f9ac582fcb
  - Linux < 6.6.157
  - Linux < 6.12.110
  - Linux < 6.18.51
  - Linux < 7.2.5
  - Linux (all versions)
published: '2026-09-24'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T13:17:17.770'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93235'
references:
  - url: 'https://git.kernel.org/stable/c/32c7f11a24268ba8d3bb50ea7f54d33f698cd253'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5eced87b7d19dbc76ebdddaf322046f9ac582fcb'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6882d458d2e403f6ba7b45542dd31a6b7531eb2e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/91ec55ddc097ccddd25ffb95a3d079b2ef362372'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c42608c09b6b5d5967bf211c255914c068c2cde1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-24T15:45:56.659Z'
epss: 0.00209
epssPercentile: 0.09817
---

## Overview

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

f2fs: fix to zero post-EOF data when extending file size

generic/794  4s ... - output mismatch (see /share/git/fstests/results//generic/794.out.bad)
    --- tests/generic/794.out   2026-06-12 08:46:32.766426241 +0800
    +++ /share/git/fstests/results//generic/794.out.bad 2026-07-05 18:32:55.000000000 +0800
    @@ -1,4 +1,16 @@
     QA output created by 794
     append_write
    +FAIL: non-zero data in gap [4080,4096) after shutdown+remount
    +000000 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a  >ZZZZZZZZZZZZZZZZ<
    +*
    +001000
     truncate_up
    ...
    (Run 'diff -u /share/git/fstests/tests/generic/794.out /share/git/fstests/results//generic/794.out.bad'  to see the entire diff)
Ran: generic/794
Failures: generic/794
Failed 1 of 1 tests

Steps of generic/794:
1. write 4096 bytes to file w/ 0x5a
2. use fiemap to get PBA of first block in file
3. truncate file to 4080
4. umount; write 4096 bytes to file w/ 0x5a directly via PBA; mount
5. extend filesize via
   a) append 4096 from offset 4096, or
   b) truncate 8192, or
   c) fallocate 4096 from offset 4096
6. verify the gap is zeroed in memory [4080,4096)
7. sync range 4096 from offset 4096; shutdown -f (flush meta before shutdown)
8. umount; mount; verify [4080,4096) is zeroed or not.

When extending file size (e.g. via truncate, fallocate, or write) across an
unaligned EOF boundary, we need to ensure that post-EOF data in the partial
page is zeroed out in pagecache and marked dirty, then writeback the cache to
persist zeroed data before committing inode w/ updated i_size.

This help to prevent stale disk data beyond the previous EOF from being exposed
after remounting or crash recovery.

Since f2fs is a LFS filesystem, we only support direct write via PBA in pinfile,
and pinfile has section-aligned filesize, so in Android, there should no problem,
but for other usage in different environment, let's fix this w/ fsync_mode=strict
mount option.

## Remediation

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