# CVE-2026-43147: Revert "PCI/IOV: Add PCI rescan-remove locking when enabling/disabling SR-IOV"

> A deadlock in the Linux kernel PCI subsystem allows local attackers to cause a denial of service by triggering recursive locking during SR-IOV device removal.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/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:** 6 May 2026
- **Updated:** 23 May 2026
- **Also known as:** BELL-CVE-2026-43147, DEBIAN-CVE-2026-43147, GHSA-5c36-jx4m-m84f, ROOT-OS-DEBIAN-11-CVE-2026-43147, ROOT-OS-UBUNTU-2204-CVE-2026-43147, ROOT-OS-UBUNTU-2404-CVE-2026-43147, UBUNTU-CVE-2026-43147

## What is CVE-2026-43147?

CVE-2026-43147 is a medium-severity vulnerability in Linux kernel, published on 6 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:

Revert "PCI/IOV: Add PCI rescan-remove locking when enabling/disabling SR-IOV"

This reverts commit 05703271c3cd ("PCI/IOV: Add PCI rescan-remove locking
when enabling/disabling SR-IOV"), which causes a deadlock by recursively
taking pci_rescan_remove_lock when sriov_del_vfs() is called as part of
pci_stop_and_remove_bus_device(). For example with the following sequence
of commands:

  $ echo <NUM> > /sys/bus/pci/devices/<pf>/sriov_numvfs
  $ echo 1 > /sys/bus/pci/devices/<pf>/remove

A trimmed trace of the deadlock on a mlx5 device is as below:

  zsh/5715 is trying to acquire lock:
  000002597926ef50 (pci_rescan_remove_lock){+.+.}-{3:3}, at: sriov_disable+0x34/0x140

  but task is already holding lock:
  000002597926ef50 (pci_rescan_remove_lock){+.+.}-{3:3}, at: pci_stop_and_remove_bus_device_locked+0x24/0x80
  ...
  Call Trace:
   [<00000259778c4f90>] dump_stack_lvl+0xc0/0x110
   [<00000259779c844e>] print_deadlock_bug+0x31e/0x330
   [<00000259779c1908>] __lock_acquire+0x16c8/0x32f0
   [<00000259779bffac>] lock_acquire+0x14c/0x350
   [<00000259789643a6>] __mutex_lock_common+0xe6/0x1520
   [<000002597896413c>] mutex_lock_nested+0x3c/0x50
   [<00000259784a07e4>] sriov_disable+0x34/0x140
   [<00000258f7d6dd80>] mlx5_sriov_disable+0x50/0x80 [mlx5_core]
   [<00000258f7d5745e>] remove_one+0x5e/0xf0 [mlx5_core]
   [<00000259784857fc>] pci_device_remove+0x3c/0xa0
   [<000002597851012e>] device_release_driver_internal+0x18e/0x280
   [<000002597847ae22>] pci_stop_bus_device+0x82/0xa0
   [<000002597847afce>] pci_stop_and_remove_bus_device_locked+0x5e/0x80
   [<00000259784972c2>] remove_store+0x72/0x90
   [<0000025977e6661a>] kernfs_fop_write_iter+0x15a/0x200
   [<0000025977d7241c>] vfs_write+0x24c/0x300
   [<0000025977d72696>] ksys_write+0x86/0x110
   [<000002597895b61c>] __do_syscall+0x14c/0x400
   [<000002597896e0ee>] system_call+0x6e/0x90

This alone is not a complete fix as it restores the issue the cited commit
tried to solve. A new fix will be provided as a follow on.

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2026-43147?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43147?

Apply the vendor's patch.

## Is CVE-2026-43147 being exploited?

There is no known exploitation of CVE-2026-43147 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-2026-43147 and fix it if it is affected.

What it is: CVE-2026-43147 is a medium-severity vulnerability in Linux kernel, published on 6 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-2026-43147 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-2026-43147/ (Markdown: https://insights.sbomify.com/CVE-2026-43147/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43147
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43147
- OSV: https://osv.dev/vulnerability/CVE-2026-43147

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43147/
Summaries are generated and may contain mistakes; the official description above is the record.