---
id: CVE-2026-89614
title: 'ntfs: bound the free-cluster bitmap scan to the volume'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ntfs: bound the free-cluster bitmap scan to the volume

  vol->lcn_empty_bits_per_page is sized from vol->nr_clusters at mount, but
  ntfs_cluster_alloc() bounds its scan o…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-125
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 11ccc9107dc460de28af90fac1f42404d9802735 <
    dc15a9f5307d5372aef3b64bf3ed7802f530c471
  - >-
    Linux >= 11ccc9107dc460de28af90fac1f42404d9802735 <
    19cac7902a8ab748e15f98ddaafcf5f8882be21d
  - Linux 7.1
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:49:46.853Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89614'
references:
  - url: 'https://git.kernel.org/stable/c/dc15a9f5307d5372aef3b64bf3ed7802f530c471'
  - url: 'https://git.kernel.org/stable/c/19cac7902a8ab748e15f98ddaafcf5f8882be21d'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89614.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89614'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532318'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89614'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89614'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89614.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00553
epssPercentile: 0.46016
scores:
  cna: 9.8
  vendor: 5.5
ingestedAt: '2026-09-14T15:23:07.474Z'
---

## Overview

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

ntfs: bound the free-cluster bitmap scan to the volume

vol->lcn_empty_bits_per_page is sized from vol->nr_clusters at mount, but
ntfs_cluster_alloc() bounds its scan of that array by the size of $Bitmap.
Those are independent on-disk quantities and the mount-time check only
rejects a $Bitmap that is too small, so an image whose $Bitmap covers more
clusters than the volume has lets the scan index past the array.  A run
whose LCN lies in that gap takes the allocator straight there, since the
caller passes the file's own last LCN as its locality hint.  KASAN reports
a slab out-of-bounds read when a file on such a volume is extended.

Clamp the scan to what that array covers, mirroring the max_index
calculation the mount-time scan already uses, and reject a decoded LCN
at or beyond nr_clusters in the mapping pairs decoder.  Conforming
volumes are unaffected.

## Affected

- `Linux >= 11ccc9107dc460de28af90fac1f42404d9802735 < dc15a9f5307d5372aef3b64bf3ed7802f530c471`
- `Linux >= 11ccc9107dc460de28af90fac1f42404d9802735 < 19cac7902a8ab748e15f98ddaafcf5f8882be21d`
- `Linux 7.1`

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89614.json)