---
id: CVE-2026-89494
title: 'ocfs2: validate lengths in dlm_mig_lockres_handler'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ocfs2: validate lengths in dlm_mig_lockres_handler

  A node receiving a DLM_MIG_LOCKRES message trusts several fields of the
  peer-supplied dlm_migratable_lockres without…
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
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 <
    4a5798253212093b9ff7d90c6cfbe348bcda1594
  - >-
    Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 <
    dce05b17db862f47ff60614017abe639b2e71cad
  - >-
    Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 <
    0e999d56917f861f97adb961617b1828c9eb4733
  - >-
    Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 <
    77686fa5bba135252d348e2dacf481fc19f60c41
  - >-
    Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 <
    f33041906885f96e190cde54e61ddc69de39e3ee
  - >-
    Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 <
    50c4cc9183e11f83427efbf770f54851f4471c02
  - >-
    Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 <
    a8facb1670b4a0612183198e758d9539ef628ed9
  - >-
    Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 <
    b54e03d9b3697d25f4a0063cf717d459c5e3ad94
  - Linux 2.6.16
published: '2026-09-11'
updated: '2026-09-14'
sourceUpdated: '2026-09-14T12:00:28.925Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89494'
references:
  - url: 'https://git.kernel.org/stable/c/4a5798253212093b9ff7d90c6cfbe348bcda1594'
  - url: 'https://git.kernel.org/stable/c/dce05b17db862f47ff60614017abe639b2e71cad'
  - url: 'https://git.kernel.org/stable/c/0e999d56917f861f97adb961617b1828c9eb4733'
  - url: 'https://git.kernel.org/stable/c/77686fa5bba135252d348e2dacf481fc19f60c41'
  - url: 'https://git.kernel.org/stable/c/f33041906885f96e190cde54e61ddc69de39e3ee'
  - url: 'https://git.kernel.org/stable/c/50c4cc9183e11f83427efbf770f54851f4471c02'
  - url: 'https://git.kernel.org/stable/c/a8facb1670b4a0612183198e758d9539ef628ed9'
  - url: 'https://git.kernel.org/stable/c/b54e03d9b3697d25f4a0063cf717d459c5e3ad94'
tags:
  - cve.org
epss: 0.00704
epssPercentile: 0.51905
ingestedAt: '2026-09-14T15:23:07.452Z'
---

## Overview

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

ocfs2: validate lengths in dlm_mig_lockres_handler

A node receiving a DLM_MIG_LOCKRES message trusts several fields of the
peer-supplied dlm_migratable_lockres without validation.  num_locks and
lockname_len are bounded only on the sending side, and the message is
never checked to actually carry num_locks migratable_lock entries.  As a
result dlm_process_recovery_data() walks mres->ml[0..num_locks) past the
kmalloc(data_len) copy of the message (an out-of-bounds read that ends in
a BUG_ON panic), and dlm_init_lockres() copies lockname_len bytes into the
fixed 32-byte o2dlm_lockname slab object (a heap out-of-bounds write). 
Both are reachable by any node in the domain.

Validate these fields right after dlm_grab(), before anything uses them --
including the not-joined error path, which already prints mres->lockname
with the unbounded lockname_len as a %.*s precision.  Reject the message
unless lockname_len <= DLM_LOCKID_NAME_MAX, num_locks <=
DLM_MAX_MIGRATABLE_LOCKS (the bound the sender already asserts), and the
payload is large enough to hold the claimed locks.  Conforming recovery
and migration messages are unaffected.

## Affected

- `Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 < 4a5798253212093b9ff7d90c6cfbe348bcda1594`
- `Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 < dce05b17db862f47ff60614017abe639b2e71cad`
- `Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 < 0e999d56917f861f97adb961617b1828c9eb4733`
- `Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 < 77686fa5bba135252d348e2dacf481fc19f60c41`
- `Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 < f33041906885f96e190cde54e61ddc69de39e3ee`
- `Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 < 50c4cc9183e11f83427efbf770f54851f4471c02`
- `Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 < a8facb1670b4a0612183198e758d9539ef628ed9`
- `Linux >= 6714d8e86bf443f6f7af50f9d432025649f091f5 < b54e03d9b3697d25f4a0063cf717d459c5e3ad94`
- `Linux 2.6.16`

## Remediation

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