---
id: CVE-2026-53029
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  fs/ntfs3: prevent uninitialized lcn caused by zero len

  syzbot reported a uninit-value in ntfs_iomap_begin [1].

  Since runs was not touched yet, run_lookup_entry() imme…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  fs/ntfs3: prevent uninitialized lcn caused by zero len

  syzbot reported a uninit-value in ntfs_iomap_begin [1].

  Since runs was not touched yet, run_lookup_entry() imme…
severity: none
published: '2026-06-24'
updated: '2026-07-10'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53029'
references:
  - url: 'https://git.kernel.org/stable/c/485f750cac3d8bdf5552a0e3d79ce5e3a03ece49'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e98266e823a1fa06fe6499df61aeaac2fd6f7a49'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00143
epssPercentile: 0.03002
ingestedAt: '2026-07-11T19:15:12.002Z'
---

## Overview

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

fs/ntfs3: prevent uninitialized lcn caused by zero len

syzbot reported a uninit-value in ntfs_iomap_begin [1].

Since runs was not touched yet, run_lookup_entry() immediately fails
and returns false, which makes the value of "*len" 0.
Simultaneously, the new value and err value are also 0, causing the
logic in attr_data_get_block_locked() to jump directly to ok, ultimately
resulting in *lcn being triggered before it is set [1].

In ntfs_iomap_begin(), the check for a 0 value in clen is moved forward
to before updating lcn to avoid this [1].

[1]
BUG: KMSAN: uninit-value in ntfs_iomap_begin+0x8c0/0x1460 fs/ntfs3/inode.c:825
 ntfs_iomap_begin+0x8c0/0x1460 fs/ntfs3/inode.c:825
 iomap_iter+0x9b7/0x1540 fs/iomap/iter.c:110

Local variable lcn created at:
 ntfs_iomap_begin+0x15d/0x1460 fs/ntfs3/inode.c:786

## Remediation

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