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Fencer Vulns
no cvss —

CVE-2025-40134 json

dm: fix NULL pointer dereference in __dm_suspend()

published 2025-11-12 11 mo ago modified 2026-11-05 3 d ago also EUVD-2025-124949

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 13%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 5.4.301, 5.10.246, 5.15.195, 6.1.156, 6.6.112, 6.12.53, 6.17.3, 6.18
  • linux Debian 12 6.1.158-1
  • linux Debian 13 6.12.57-1
  • linux Debian 14 6.17.6-1

debian advisories DEBIAN-CVE-2025-40134

  • linux Ubuntu 22.04 LTS 5.15.0-170.180
  • linux Ubuntu 24.04 LTS 6.8.0-106.106
  • linux Ubuntu 25.10 6.17.0-14.14
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1100.107
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1050.53
  • linux-aws Ubuntu 25.10 6.17.0-1007.7
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1100.109
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1052.55

ubuntu advisories UBUNTU-CVE-2025-40134

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 9 5.14.0-687.5.1.el9_8
  • rv RHEL 9 5.14.0-687.5.1.el9_8
  • perf RHEL 9 5.14.0-687.5.1.el9_8
  • rtla RHEL 9 5.14.0-687.5.1.el9_8
  • libperf RHEL 9 5.14.0-687.5.1.el9_8
  • kernel-rt RHEL 9 5.14.0-687.5.1.el9_8
  • kernel-64k RHEL 9 5.14.0-687.5.1.el9_8
  • kernel-core RHEL 9 5.14.0-687.5.1.el9_8

red hat advisories RHSA-2026:18587RHSA-2026:18134

  • kernel-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
  • kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
  • kernel-source Linux Micro 6.1, Linux Micro 6.0 6.4.0-39.1
  • kernel-default Linux Micro 6.1, Linux Micro 6.0 6.4.0-39.1
  • kernel-kvmsmall Linux Micro 6.1, Linux Micro 6.0 6.4.0-39.1
  • kernel-default-base Linux Micro 6.1, Linux Micro 6.0 6.4.0-39.1.21.16
  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.28.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.28.1

suse advisories SUSE-SU-2026:20845-1SUSE-SU-2026:20876-1SUSE-SU-2026:20477-1SUSE-SU-2026:20498-1SUSE-SU-2026:0315-1SUSE-SU-2026:0293-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.8.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.8.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.8.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.8.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.8.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.8.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.8.1
  • kernel-kvmsmall openSUSE Leap 16.0 6.12.0-160000.8.1

opensuse advisories openSUSE-SU-2025:20172-1

  • kernel AlmaLinux 10 6.12.0-211.7.1.el10_2
  • rv AlmaLinux 10 6.12.0-211.7.1.el10_2
  • perf AlmaLinux 10 6.12.0-211.7.1.el10_2
  • rtla AlmaLinux 10 6.12.0-211.7.1.el10_2
  • libperf AlmaLinux 10 6.12.0-211.7.1.el10_2
  • kernel-rt AlmaLinux 10 6.12.0-211.7.1.el10_2
  • kernel-64k AlmaLinux 10 6.12.0-211.7.1.el10_2
  • kernel-core AlmaLinux 10 6.12.0-211.7.1.el10_2

almalinux advisories ALSA-2026:18134ALSA-2026:18587

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-40134 updated cvss 4.7

kernel: dm: fix NULL pointer dereference in __dm_suspend()

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.5.1.el9_8, perf 5.14.0-687.5.1.el9_8, rtla 5.14.0-687.5.1.el9_8, python3-perf 5.14.0-687.5.1.el9_8, kernel-devel-matched 5.14.0-687.5.1.el9_8, kernel-64k-devel-matched 5.14.0-687.5.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:18587
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.7.1.el10_2, perf 6.12.0-211.7.1.el10_2, rtla 6.12.0-211.7.1.el10_2, python3-perf 6.12.0-211.7.1.el10_2, kernel-devel-matched 6.12.0-211.7.1.el10_2, kernel-64k-devel-matched 6.12.0-211.7.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:18134
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.5.1.el9_8, kernel-64k 5.14.0-687.5.1.el9_8, kernel-core 5.14.0-687.5.1.el9_8, kernel-tools 5.14.0-687.5.1.el9_8, kernel-modules 5.14.0-687.5.1.el9_8, kernel-64k-core 5.14.0-687.5.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:18587
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.7.1.el10_2, kernel-64k 6.12.0-211.7.1.el10_2, kernel-core 6.12.0-211.7.1.el10_2, kernel-tools 6.12.0-211.7.1.el10_2, kernel-modules 6.12.0-211.7.1.el10_2, kernel-64k-core 6.12.0-211.7.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:18134
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.5.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.5.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.5.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.5.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.5.1.el9_8
    fixed: vendor fix RHSA-2026:18587
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.7.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.7.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.7.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.7.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.7.1.el10_2
    fixed: vendor fix RHSA-2026:18134
show 4 more
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.5.1.el9_8, kernel-rt-64k 5.14.0-687.5.1.el9_8, kernel-rt-core 5.14.0-687.5.1.el9_8, kernel-rt-modules 5.14.0-687.5.1.el9_8, kernel-rt-64k-core 5.14.0-687.5.1.el9_8, kernel-rt-debug-core 5.14.0-687.5.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:18587
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.7.1.el10_2, kernel-rt-64k 6.12.0-211.7.1.el10_2, kernel-rt-core 6.12.0-211.7.1.el10_2, kernel-rt-modules 6.12.0-211.7.1.el10_2, kernel-rt-64k-core 6.12.0-211.7.1.el10_2, kernel-rt-debug-core 6.12.0-211.7.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:18134
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.5.1.el9_8, kernel-rt-core 5.14.0-687.5.1.el9_8, kernel-rt-modules 5.14.0-687.5.1.el9_8, kernel-rt-debug-core 5.14.0-687.5.1.el9_8, kernel-rt-modules-core 5.14.0-687.5.1.el9_8, kernel-rt-debug-modules 5.14.0-687.5.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:18587
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.7.1.el10_2, kernel-rt-core 6.12.0-211.7.1.el10_2, kernel-rt-modules 6.12.0-211.7.1.el10_2, kernel-rt-debug-core 6.12.0-211.7.1.el10_2, kernel-rt-modules-core 6.12.0-211.7.1.el10_2, kernel-rt-debug-modules 6.12.0-211.7.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:18134

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 d ago

Exploit prediction

0.23% chance of exploitation in the next 30 days, higher than 13% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.