CVE-2025-40134 Affecting kernel-rt-modules package, versions *


Severity

Recommended
medium

Based on CentOS security rating.

Threat Intelligence

EPSS
0.02% (6th percentile)

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  • Snyk IDSNYK-CENTOS8-KERNELRTMODULES-13993872
  • published14 Nov 2025
  • disclosed12 Nov 2025

Introduced: 12 Nov 2025

NewCVE-2025-40134  (opens in a new tab)

How to fix?

There is no fixed version for Centos:8 kernel-rt-modules.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-modules package and not the kernel-rt-modules package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

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

dm: fix NULL pointer dereference in __dm_suspend()

There is a race condition between dm device suspend and table load that can lead to null pointer dereference. The issue occurs when suspend is invoked before table load completes:

BUG: kernel NULL pointer dereference, address: 0000000000000054 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 6 PID: 6798 Comm: dmsetup Not tainted 6.6.0-g7e52f5f0ca9b #62 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:blk_mq_wait_quiesce_done+0x0/0x50 Call Trace: <TASK> blk_mq_quiesce_queue+0x2c/0x50 dm_stop_queue+0xd/0x20 __dm_suspend+0x130/0x330 dm_suspend+0x11a/0x180 dev_suspend+0x27e/0x560 ctl_ioctl+0x4cf/0x850 dm_ctl_ioctl+0xd/0x20 vfs_ioctl+0x1d/0x50 __se_sys_ioctl+0x9b/0xc0 __x64_sys_ioctl+0x19/0x30 x64_sys_call+0x2c4a/0x4620 do_syscall_64+0x9e/0x1b0

The issue can be triggered as below:

T1 T2 dm_suspend table_load __dm_suspend dm_setup_md_queue dm_mq_init_request_queue blk_mq_init_allocated_queue => q->mq_ops = set->ops; (1) dm_stop_queue / dm_wait_for_completion => q->tag_set NULL pointer! (2) => q->tag_set = set; (3)

Fix this by checking if a valid table (map) exists before performing request-based suspend and waiting for target I/O. When map is NULL, skip these table-dependent suspend steps.

Even when map is NULL, no I/O can reach any target because there is no table loaded; I/O submitted in this state will fail early in the DM layer. Skipping the table-dependent suspend logic in this case is safe and avoids NULL pointer dereferences.

CVSS Base Scores

version 3.1