---
id: CVE-2026-74401
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  dlm: fix add msg handle in send_queue ordered

  In a benchmark scenario triggering a lot of requests that triggers a lot
  of DLM messages on the network it can be that th…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  dlm: fix add msg handle in send_queue ordered

  In a benchmark scenario triggering a lot of requests that triggers a lot
  of DLM messages on the network it can be that th…
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'
cwe:
  - CWE-416
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 6
  - enterprise_linux 9
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T20:17:25.567'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74401'
references:
  - url: 'https://git.kernel.org/stable/c/4d45250b1d22960f86d83245be188b16e456218b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6369619f1b665f12d8c99cc6ff733c64eb08b22e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/712714f818d83373847874ab0f8e426be79296cf'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ae9e534e502a0f48c12baf83608c5de0ff0eab11'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d2248cb70c070f8f04762872772e155b59016f17'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74401.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-74401'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2516864'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-74401'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74401'
  - url: 'https://kernelcve.org/list/?q=CVE-2026-74401'
  - url: >-
      https://lore.kernel.org/linux-cve-announce/2026081509-CVE-2026-74401-2c5f@gregkh/T
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00652
epssPercentile: 0.51054
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T18:55:33.158512Z'
scores:
  nvd: 9.8
  vendor: 5.3
  cna: 9.8
ingestedAt: '2026-10-16T19:46:24.368Z'
---

## Overview

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

dlm: fix add msg handle in send_queue ordered

In a benchmark scenario triggering a lot of requests that triggers a lot
of DLM messages on the network it can be that the mh->seq is not ordered
according the oldest seq number. This ordering is required by
dlm_receive_ack as "before(mh->seq, seq)" will stop to check for older
sequence numbers that are ordered in the tail of "node->send_queue".

The side effects of not having it correct ordered regarding
"before(mh->seq, seq)" are refcounting issues and use-after free.

I only was able to reproduce this issue in a experimental DLM branch
and a user space DLM benchmark that uses io_uring. After changing this I
don't experienced any refcounting with the sending buffer issues anymore.

## 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 6, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 9 · updated 2026-10-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74401.json)