dm: fix NULL pointer dereference in __dm_suspend()
Key facts
- Attack vector
- —
- Privileges required
- —
- User interaction
- —
- Attack complexity
- —
- Impact type
- —
- Confidentiality · integrity · availability
- —
- Fix status
- Partial Red Hat: 10 fixed, 4 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.4.301, 5.10.246, 5.15.195, 6.1.156, 6.6.112, 6.12.53, 6.17.3, 6.18
Red Hat 2 advisories
- RHSA-2026:18587 Released 2026-05-19 · Red Hat rating Moderatekernel security update
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.5.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.5.1.el9_8, kernel-64k-devel-5.14.0-687.5.1.el9_8 +12
- 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-64k-core-5.14.0-687.5.1.el9_8 +28
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.5.1.el9_8, libperf-5.14.0-687.5.1.el9_8
- 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-64k-core-5.14.0-687.5.1.el9_8 +21
- 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-debug-5.14.0-687.5.1.el9_8 +9
- RHSA-2026:18134 Released 2026-05-19 · Red Hat rating Moderatekernel security update
- Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.7.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.7.1.el10_2, kernel-64k-devel-6.12.0-211.7.1.el10_2 +12
- 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-64k-core-6.12.0-211.7.1.el10_2 +29
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.7.1.el10_2, libperf-6.12.0-211.7.1.el10_2
- 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-64k-core-6.12.0-211.7.1.el10_2 +21
- 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-debug-6.12.0-211.7.1.el10_2 +9
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:18134 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:18587 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:18134 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2026:18587 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) | Fixed | RHSA-2026:18134 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2026:18587 |
| Red Hat Enterprise Linux Real Time (v. 10) | Fixed | RHSA-2026:18134 |
| Red Hat Enterprise Linux Real Time (v. 9) | Fixed | RHSA-2026:18587 |
| Red Hat Enterprise Linux Real Time for NFV (v. 10) | Fixed | RHSA-2026:18134 |
| Red Hat Enterprise Linux Real Time for NFV (v. 9) | Fixed | RHSA-2026:18587 |
Timeline
- 2026-10-02 Threatist record created from CVE-2025-40134
- 2026-10-03 Alias added: GHSA-m29g-8vpf-pc8m
- 2026-11-05 CISA SSVC decision points changed
References
Other 8
- https://git.kernel.org/stable/c/9dc43ea6a20ff83fe9a5fe4be47ae0fbf2409b98
- https://git.kernel.org/stable/c/30f95b7eda5966b81cb221bd569c0f095a068cf6
- https://git.kernel.org/stable/c/a0e54bd8d7ea79127fe9920df3ae36f85e79ac7c
- https://git.kernel.org/stable/c/a802901b75e13cc306f1b7ab0f062135c8034e9e
- https://git.kernel.org/stable/c/846cafc4725ca727d94f9c4b5f789c1a7c8fb6fe
- https://git.kernel.org/stable/c/19ca4528666990be376ac3eb6fe667b03db5324d
- https://git.kernel.org/stable/c/331c2dd8ca8bad1a3ac10cce847ffb76158eece4
- https://git.kernel.org/stable/c/8d33a030c566e1f105cd5bf27f37940b6367f3be
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Sources
- CVE-2025-40134 · CVE Program
- CVE-2025-40134 · NVD
- FIRST EPSS
- GHSA-m29g-8vpf-pc8m · GitHub Advisory Database · CC BY 4.0
- CVE-2025-40134 · Red Hat security data · CC BY 4.0
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