CVE-2026-74401

dlm: fix add msg handle in send_queue ordered

State: Published
Severity: 9.8 Critical
Published: Aug 15, 2026
Updated: Oct 30, 2026
Reserved: Aug 15, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	9.8 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	489d8e559c6596eb08e16447d9830bc39afbe54e to before 482606fea302d8bab86901d7426c3716980d99a8Affected 489d8e559c6596eb08e16447d9830bc39afbe54e to before ae9e534e502a0f48c12baf83608c5de0ff0eab11Affected 489d8e559c6596eb08e16447d9830bc39afbe54e to before 6369619f1b665f12d8c99cc6ff733c64eb08b22eAffected 489d8e559c6596eb08e16447d9830bc39afbe54e to before 712714f818d83373847874ab0f8e426be79296cfAffected 489d8e559c6596eb08e16447d9830bc39afbe54e to before 4d45250b1d22960f86d83245be188b16e456218bAffected 489d8e559c6596eb08e16447d9830bc39afbe54e to before d2248cb70c070f8f04762872772e155b59016f17Affected
LinuxLinux	5.14Affected before 5.14Not affected 6.1.191 through 6.1.Not affected 6.6.145 through 6.6.Not affected 6.12.97 through 6.12.Not affected 6.18.40 through 6.18.Not affected 7.1.5 through 7.1.*Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

489d8e559c6596eb08e16447d9830bc39afbe54e to before 482606fea302d8bab86901d7426c3716980d99a8Affected
489d8e559c6596eb08e16447d9830bc39afbe54e to before ae9e534e502a0f48c12baf83608c5de0ff0eab11Affected
489d8e559c6596eb08e16447d9830bc39afbe54e to before 6369619f1b665f12d8c99cc6ff733c64eb08b22eAffected
489d8e559c6596eb08e16447d9830bc39afbe54e to before 712714f818d83373847874ab0f8e426be79296cfAffected
489d8e559c6596eb08e16447d9830bc39afbe54e to before 4d45250b1d22960f86d83245be188b16e456218bAffected
489d8e559c6596eb08e16447d9830bc39afbe54e to before d2248cb70c070f8f04762872772e155b59016f17Affected

LinuxLinux

5.14Affected
before 5.14Not affected
6.1.191 through 6.1.*Not affected
6.6.145 through 6.6.*Not affected
6.12.97 through 6.12.*Not affected
6.18.40 through 6.18.*Not affected
7.1.5 through 7.1.*Not affected
7.2 and laterNot affected

References

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