# CVE-2026-43448: nvme-pci: Fix race bug in nvme_poll_irqdisable()
> A race condition in the Linux kernel NVMe driver can cause unbalanced IRQ enable/disable calls, leading to system warnings and potential instability.
- **Severity:** Medium 4.7 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 May 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-43448, DEBIAN-CVE-2026-43448, GHSA-938f-6jj9-x227, ROOT-OS-DEBIAN-11-CVE-2026-43448, ROOT-OS-UBUNTU-2204-CVE-2026-43448, ROOT-OS-UBUNTU-2404-CVE-2026-43448, UBUNTU-CVE-2026-43448
## What is CVE-2026-43448?
CVE-2026-43448 is a medium-severity vulnerability in Linux kernel, published on 8 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
### Official description
In the Linux kernel, the following vulnerability has been resolved:
nvme-pci: Fix race bug in nvme_poll_irqdisable()
In the following scenario, pdev can be disabled between (1) and (3) by
(2). This sets pdev->msix_enabled = 0. Then, pci_irq_vector() will
return MSI-X IRQ(>15) for (1) whereas return INTx IRQ(<=15) for (2).
This causes IRQ warning because it tries to enable INTx IRQ that has
never been disabled before.
To fix this, save IRQ number into a local variable and ensure
disable_irq() and enable_irq() operate on the same IRQ number. Even if
pci_free_irq_vectors() frees the IRQ concurrently, disable_irq() and
enable_irq() on a stale IRQ number is still valid and safe, and the
depth accounting reamins balanced.
task 1:
nvme_poll_irqdisable()
disable_irq(pci_irq_vector(pdev, nvmeq->cq_vector)) ...(1)
enable_irq(pci_irq_vector(pdev, nvmeq->cq_vector)) ...(3)
task 2:
nvme_reset_work()
nvme_dev_disable()
pdev->msix_enable = 0; ...(2)
crash log:
------------[ cut here ]------------
Unbalanced enable for IRQ 10
WARNING: kernel/irq/manage.c:753 at __enable_irq+0x102/0x190 kernel/irq/manage.c:753, CPU#1: kworker/1:0H/26
Modules linked in:
CPU: 1 UID: 0 PID: 26 Comm: kworker/1:0H Not tainted 6.19.0-dirty #9 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
Workqueue: kblockd blk_mq_timeout_work
RIP: 0010:__enable_irq+0x107/0x190 kernel/irq/manage.c:753
Code: ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 79 48 8d 3d 2e 7a 3f 05 41 8b 74 24 2c <67> 48 0f b9 3a e8 ef b9 21 00 5b 41 5c 5d e9 46 54 66 03 e8 e1 b9
RSP: 0018:ffffc900001bf550 EFLAGS: 00010046
RAX: 0000000000000007 RBX: 0000000000000000 RCX: ffffffffb20c0e90
RDX: 0000000000000000 RSI: 000000000000000a RDI: ffffffffb74b88f0
RBP: ffffc900001bf560 R08: ffff88800197cf00 R09: 0000000000000001
R10: 0000000000000003 R11: 0000000000000003 R12: ffff8880012a6000
R13: 1ffff92000037eae R14: 000000000000000a R15: 0000000000000293
FS: 0000000000000000(0000) GS:ffff8880b49f7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555da4a25fa8 CR3: 00000000208e8000 CR4: 00000000000006f0
Call Trace:
enable_irq+0x121/0x1e0 kernel/irq/manage.c:797
nvme_poll_irqdisable+0x162/0x1c0 drivers/nvme/host/pci.c:1494
nvme_timeout+0x965/0x14b0 drivers/nvme/host/pci.c:1744
blk_mq_rq_timed_out block/blk-mq.c:1653 [inline]
blk_mq_handle_expired+0x227/0x2d0 block/blk-mq.c:1721
bt_iter+0x2fc/0x3a0 block/blk-mq-tag.c:292
__sbitmap_for_each_set include/linux/sbitmap.h:269 [inline]
sbitmap_for_each_set include/linux/sbitmap.h:290 [inline]
bt_for_each block/blk-mq-tag.c:324 [inline]
blk_mq_queue_tag_busy_iter+0x969/0x1e80 block/blk-mq-tag.c:536
blk_mq_timeout_work+0x627/0x870 block/blk-mq.c:1763
process_one_work+0x956/0x1aa0 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x65c/0xe60 kernel/workqueue.c:3421
kthread+0x41a/0x930 kernel/kthread.c:463
ret_from_fork+0x6f8/0x8c0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
irq event stamp: 74478
hardirqs last enabled at (74477): [] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline]
hardirqs last enabled at (74477): [] _raw_spin_unlock_irq+0x2c/0x60 kernel/locking/spinlock.c:202
hardirqs last disabled at (74478): [] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
hardirqs last disabled at (74478): [] _raw_spin_lock_irqsave+0x85/0xa0 kernel/locking/spinlock.c:162
softirqs last enabled at (74304): [] __do_softirq kernel/softirq.c:656 [inline]
softirqs last enabled at (74304): [] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last enabled at (74304): [] __irq_exit_rcu+0xdc/0x120
---truncated---
Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)
## Which versions are affected by CVE-2026-43448?
It affects 1 product.
Products: Linux kernel.
## How do I fix CVE-2026-43448?
Apply the vendor's patch.
## Is CVE-2026-43448 being exploited?
There is no known exploitation of CVE-2026-43448 in the wild and no public exploit code.
## Other vulnerabilities in Linux kernel
- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)
## Fix prompt for AI coding agents
```text
Check this codebase for CVE-2026-43448 and fix it if it is affected.
What it is: CVE-2026-43448 is a medium-severity vulnerability in Linux kernel, published on 8 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-43448 in the wild and no public exploit code.
Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-43448/ (Markdown: https://insights.sbomify.com/CVE-2026-43448/index.md)
```
## Sources
- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43448
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43448
- OSV: https://osv.dev/vulnerability/CVE-2026-43448
---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43448/
Summaries are generated and may contain mistakes; the official description above is the record.