---
id: CVE-2026-89574
title: 'dm array: validate array block headers on read'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  dm array: validate array block headers on read

  array_block_check() validates blocknr and csum and nothing else, while
  node_check(), next to it, has bounded the structu…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-125
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 6513c29f44f2cc970c0e9fecfe5a6526c3e73025 <
    0e3b8f371c385c212b6e6f76c66f5b3f5bcfea62
  - >-
    Linux >= 6513c29f44f2cc970c0e9fecfe5a6526c3e73025 <
    67adda7ed5da3e3b64f5b9021a02c21fb374fd9c
  - >-
    Linux >= 6513c29f44f2cc970c0e9fecfe5a6526c3e73025 <
    b33f76d33aaeacf3baf3370d8d64985169b36600
  - >-
    Linux >= 6513c29f44f2cc970c0e9fecfe5a6526c3e73025 <
    9808ddffb4bc659352df3020cd84d9d864820ee5
  - >-
    Linux >= 6513c29f44f2cc970c0e9fecfe5a6526c3e73025 <
    2965787723084835b18dfe993cd450ebf5bd4540
  - Linux 3.9
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T19:24:26.489606Z'
published: '2026-09-11'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T12:47:56.785Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89574'
references:
  - url: 'https://git.kernel.org/stable/c/0e3b8f371c385c212b6e6f76c66f5b3f5bcfea62'
  - url: 'https://git.kernel.org/stable/c/67adda7ed5da3e3b64f5b9021a02c21fb374fd9c'
  - url: 'https://git.kernel.org/stable/c/b33f76d33aaeacf3baf3370d8d64985169b36600'
  - url: 'https://git.kernel.org/stable/c/9808ddffb4bc659352df3020cd84d9d864820ee5'
  - url: 'https://git.kernel.org/stable/c/2965787723084835b18dfe993cd450ebf5bd4540'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89574.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89574'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532117'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89574'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89574'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89574.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00168
epssPercentile: 0.06171
scores:
  cna: 7.8
  vendor: 5.5
ingestedAt: '2026-09-14T15:23:07.474Z'
---

## Overview

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

dm array: validate array block headers on read

array_block_check() validates blocknr and csum and nothing else, while
node_check(), next to it, has bounded the structural fields since both
were written. dm_array_cursor_next() takes its loop bound from the
on-disk nr_entries and element_at() is unguarded pointer arithmetic, so
a count larger than the block holds keeps the cursor in one block while
the index grows past it and the read walks off the dm-bufio buffer --
dm_cache_load_mappings() drives it once per cache block at activation.

Check the header against itself: reject a zero value_size, require
max_entries to equal calc_max_entries() for that value_size and block
size, and require nr_entries to fit. Equality rather than an upper bound,
since a count below the real capacity trips BUG_ON() in fill_ablock() and
trim_ablock(). Metadata dm-array writes satisfies all three.

## Affected

- `Linux >= 6513c29f44f2cc970c0e9fecfe5a6526c3e73025 < 0e3b8f371c385c212b6e6f76c66f5b3f5bcfea62`
- `Linux >= 6513c29f44f2cc970c0e9fecfe5a6526c3e73025 < 67adda7ed5da3e3b64f5b9021a02c21fb374fd9c`
- `Linux >= 6513c29f44f2cc970c0e9fecfe5a6526c3e73025 < b33f76d33aaeacf3baf3370d8d64985169b36600`
- `Linux >= 6513c29f44f2cc970c0e9fecfe5a6526c3e73025 < 9808ddffb4bc659352df3020cd84d9d864820ee5`
- `Linux >= 6513c29f44f2cc970c0e9fecfe5a6526c3e73025 < 2965787723084835b18dfe993cd450ebf5bd4540`
- `Linux 3.9`

## 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 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89574.json)