# CVE-2026-31695: wifi: virt_wifi: remove SET_NETDEV_DEV to avoid use-after-free

> A use-after-free vulnerability in the Linux kernel's virt_wifi driver allows attackers to cause a denial of service or potentially execute code via ethtool operations.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 1 May 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-31695, DEBIAN-CVE-2026-31695, GHSA-5qrg-p9jr-4m22, ROOT-OS-UBUNTU-2204-CVE-2026-31695, ROOT-OS-UBUNTU-2404-CVE-2026-31695, UBUNTU-CVE-2026-31695

## What is CVE-2026-31695?

CVE-2026-31695 is a high-severity use after free vulnerability in Linux kernel, published on 1 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:

wifi: virt_wifi: remove SET_NETDEV_DEV to avoid use-after-free

Currently we execute `SET_NETDEV_DEV(dev, &priv->lowerdev->dev)` for
the virt_wifi net devices. However, unregistering a virt_wifi device in
netdev_run_todo() can happen together with the device referenced by
SET_NETDEV_DEV().

It can result in use-after-free during the ethtool operations performed
on a virt_wifi device that is currently being unregistered. Such a net
device can have the `dev.parent` field pointing to the freed memory,
but ethnl_ops_begin() calls `pm_runtime_get_sync(dev->dev.parent)`.

Let's remove SET_NETDEV_DEV for virt_wifi to avoid bugs like this:

 ==================================================================
 BUG: KASAN: slab-use-after-free in __pm_runtime_resume+0xe2/0xf0
 Read of size 2 at addr ffff88810cfc46f8 by task pm/606

 Call Trace:
  <TASK>
  dump_stack_lvl+0x4d/0x70
  print_report+0x170/0x4f3
  ? __pfx__raw_spin_lock_irqsave+0x10/0x10
  kasan_report+0xda/0x110
  ? __pm_runtime_resume+0xe2/0xf0
  ? __pm_runtime_resume+0xe2/0xf0
  __pm_runtime_resume+0xe2/0xf0
  ethnl_ops_begin+0x49/0x270
  ethnl_set_features+0x23c/0xab0
  ? __pfx_ethnl_set_features+0x10/0x10
  ? kvm_sched_clock_read+0x11/0x20
  ? local_clock_noinstr+0xf/0xf0
  ? local_clock+0x10/0x30
  ? kasan_save_track+0x25/0x60
  ? __kasan_kmalloc+0x7f/0x90
  ? genl_family_rcv_msg_attrs_parse.isra.0+0x150/0x2c0
  genl_family_rcv_msg_doit+0x1e7/0x2c0
  ? __pfx_genl_family_rcv_msg_doit+0x10/0x10
  ? __pfx_cred_has_capability.isra.0+0x10/0x10
  ? stack_trace_save+0x8e/0xc0
  genl_rcv_msg+0x411/0x660
  ? __pfx_genl_rcv_msg+0x10/0x10
  ? __pfx_ethnl_set_features+0x10/0x10
  netlink_rcv_skb+0x121/0x380
  ? __pfx_genl_rcv_msg+0x10/0x10
  ? __pfx_netlink_rcv_skb+0x10/0x10
  ? __pfx_down_read+0x10/0x10
  genl_rcv+0x23/0x30
  netlink_unicast+0x60f/0x830
  ? __pfx_netlink_unicast+0x10/0x10
  ? __pfx___alloc_skb+0x10/0x10
  netlink_sendmsg+0x6ea/0xbc0
  ? __pfx_netlink_sendmsg+0x10/0x10
  ? __futex_queue+0x10b/0x1f0
  ____sys_sendmsg+0x7a2/0x950
  ? copy_msghdr_from_user+0x26b/0x430
  ? __pfx_____sys_sendmsg+0x10/0x10
  ? __pfx_copy_msghdr_from_user+0x10/0x10
  ___sys_sendmsg+0xf8/0x180
  ? __pfx____sys_sendmsg+0x10/0x10
  ? __pfx_futex_wait+0x10/0x10
  ? fdget+0x2e4/0x4a0
  __sys_sendmsg+0x11f/0x1c0
  ? __pfx___sys_sendmsg+0x10/0x10
  do_syscall_64+0xe2/0x570
  ? exc_page_fault+0x66/0xb0
  entry_SYSCALL_64_after_hwframe+0x77/0x7f
  </TASK>

This fix may be combined with another one in the ethtool subsystem:
https://lore.kernel.org/all/20260322075917.254874-1-alex.popov@linux.com/T/#u

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-31695?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31695?

Apply the vendor's patch.

## Is CVE-2026-31695 being exploited?

There is no known exploitation of CVE-2026-31695 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-2026-31695 and fix it if it is affected.

What it is: CVE-2026-31695 is a high-severity use after free vulnerability in Linux kernel, published on 1 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-2026-31695 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-2026-31695/ (Markdown: https://insights.sbomify.com/CVE-2026-31695/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31695
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31695
- OSV: https://osv.dev/vulnerability/CVE-2026-31695

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31695/
Summaries are generated and may contain mistakes; the official description above is the record.