---
id: CVE-2026-74401
title: 'dlm: fix add msg handle in send_queue ordered'
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'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 489d8e559c6596eb08e16447d9830bc39afbe54e <
    ae9e534e502a0f48c12baf83608c5de0ff0eab11
  - >-
    Linux >= 489d8e559c6596eb08e16447d9830bc39afbe54e <
    6369619f1b665f12d8c99cc6ff733c64eb08b22e
  - >-
    Linux >= 489d8e559c6596eb08e16447d9830bc39afbe54e <
    712714f818d83373847874ab0f8e426be79296cf
  - >-
    Linux >= 489d8e559c6596eb08e16447d9830bc39afbe54e <
    4d45250b1d22960f86d83245be188b16e456218b
  - >-
    Linux >= 489d8e559c6596eb08e16447d9830bc39afbe54e <
    d2248cb70c070f8f04762872772e155b59016f17
  - Linux 5.14
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T18:55:33.158512Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T19:05:42.033Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-74401'
references:
  - url: 'https://git.kernel.org/stable/c/ae9e534e502a0f48c12baf83608c5de0ff0eab11'
  - url: 'https://git.kernel.org/stable/c/6369619f1b665f12d8c99cc6ff733c64eb08b22e'
  - url: 'https://git.kernel.org/stable/c/712714f818d83373847874ab0f8e426be79296cf'
  - url: 'https://git.kernel.org/stable/c/4d45250b1d22960f86d83245be188b16e456218b'
  - url: 'https://git.kernel.org/stable/c/d2248cb70c070f8f04762872772e155b59016f17'
tags:
  - cve.org
epss: 0.00652
epssPercentile: 0.50217
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.

## Affected

- `Linux >= 489d8e559c6596eb08e16447d9830bc39afbe54e < ae9e534e502a0f48c12baf83608c5de0ff0eab11`
- `Linux >= 489d8e559c6596eb08e16447d9830bc39afbe54e < 6369619f1b665f12d8c99cc6ff733c64eb08b22e`
- `Linux >= 489d8e559c6596eb08e16447d9830bc39afbe54e < 712714f818d83373847874ab0f8e426be79296cf`
- `Linux >= 489d8e559c6596eb08e16447d9830bc39afbe54e < 4d45250b1d22960f86d83245be188b16e456218b`
- `Linux >= 489d8e559c6596eb08e16447d9830bc39afbe54e < d2248cb70c070f8f04762872772e155b59016f17`
- `Linux 5.14`

## Remediation

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