---
id: CVE-2023-53101
title: 'ext4: zero i_disksize when initializing the bootloader inode'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ext4: zero i_disksize when initializing the bootloader inode

  If the boot loader inode has never been used before, the
  EXT4_IOC_SWAP_BOOT inode will initialize it, incl…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 <
    d6c1447e483c05dbcfb3ff77ac04237a82070b8c
  - >-
    Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 <
    59eee0cdf8c036f554add97a4da7c06d7a9ff34a
  - >-
    Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 <
    0d8a6c9a6415999fee1259ccf1796480c026b7d6
  - >-
    Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 <
    3f00c476da8fe7c4c34ea16abb55d74127120413
  - >-
    Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 <
    01a821aacc64d4b05dafd239dbc9b7856686002f
  - >-
    Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 <
    9cb27b1e76f0cc886ac09055bc41c0ab3f205167
  - >-
    Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 <
    9e9a4cc5486356158554f6ad73027d8635a48b34
  - >-
    Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 <
    f5361da1e60d54ec81346aee8e3d8baf1be0b762
  - Linux 3.10
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T20:17:14.306407Z'
published: '2025-05-02'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T20:21:00.964Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2023-53101'
references:
  - url: 'https://git.kernel.org/stable/c/d6c1447e483c05dbcfb3ff77ac04237a82070b8c'
  - url: 'https://git.kernel.org/stable/c/59eee0cdf8c036f554add97a4da7c06d7a9ff34a'
  - url: 'https://git.kernel.org/stable/c/0d8a6c9a6415999fee1259ccf1796480c026b7d6'
  - url: 'https://git.kernel.org/stable/c/3f00c476da8fe7c4c34ea16abb55d74127120413'
  - url: 'https://git.kernel.org/stable/c/01a821aacc64d4b05dafd239dbc9b7856686002f'
  - url: 'https://git.kernel.org/stable/c/9cb27b1e76f0cc886ac09055bc41c0ab3f205167'
  - url: 'https://git.kernel.org/stable/c/9e9a4cc5486356158554f6ad73027d8635a48b34'
  - url: 'https://git.kernel.org/stable/c/f5361da1e60d54ec81346aee8e3d8baf1be0b762'
tags:
  - cve.org
epss: 0.00204
epssPercentile: 0.10481
ingestedAt: '2026-11-05T22:38:31.769Z'
---

## Overview

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

ext4: zero i_disksize when initializing the bootloader inode

If the boot loader inode has never been used before, the
EXT4_IOC_SWAP_BOOT inode will initialize it, including setting the
i_size to 0.  However, if the "never before used" boot loader has a
non-zero i_size, then i_disksize will be non-zero, and the
inconsistency between i_size and i_disksize can trigger a kernel
warning:

 WARNING: CPU: 0 PID: 2580 at fs/ext4/file.c:319
 CPU: 0 PID: 2580 Comm: bb Not tainted 6.3.0-rc1-00004-g703695902cfa
 RIP: 0010:ext4_file_write_iter+0xbc7/0xd10
 Call Trace:
  vfs_write+0x3b1/0x5c0
  ksys_write+0x77/0x160
  __x64_sys_write+0x22/0x30
  do_syscall_64+0x39/0x80

Reproducer:
 1. create corrupted image and mount it:
       mke2fs -t ext4 /tmp/foo.img 200
       debugfs -wR "sif <5> size 25700" /tmp/foo.img
       mount -t ext4 /tmp/foo.img /mnt
       cd /mnt
       echo 123 > file
 2. Run the reproducer program:
       posix_memalign(&buf, 1024, 1024)
       fd = open("file", O_RDWR | O_DIRECT);
       ioctl(fd, EXT4_IOC_SWAP_BOOT);
       write(fd, buf, 1024);

Fix this by setting i_disksize as well as i_size to zero when
initiaizing the boot loader inode.

## Affected

- `Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 < d6c1447e483c05dbcfb3ff77ac04237a82070b8c`
- `Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 < 59eee0cdf8c036f554add97a4da7c06d7a9ff34a`
- `Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 < 0d8a6c9a6415999fee1259ccf1796480c026b7d6`
- `Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 < 3f00c476da8fe7c4c34ea16abb55d74127120413`
- `Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 < 01a821aacc64d4b05dafd239dbc9b7856686002f`
- `Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 < 9cb27b1e76f0cc886ac09055bc41c0ab3f205167`
- `Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 < 9e9a4cc5486356158554f6ad73027d8635a48b34`
- `Linux >= 393d1d1d76933886d5e1ce603214c9987589c6d5 < f5361da1e60d54ec81346aee8e3d8baf1be0b762`
- `Linux 3.10`

## Remediation

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