# CVE-2026-31722: usb: gadget: f_rndis: Fix net_device lifecycle with device_move

> A dangling sysfs symlink in the Linux kernel USB RNDIS gadget driver can cause a null pointer dereference and system crash during device unbinding.

- **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:** 1 May 2026
- **Updated:** 21 Oct 2026
- **Also known as:** BELL-CVE-2026-31722, DEBIAN-CVE-2026-31722, GHSA-gx44-7282-c76j, ROOT-OS-DEBIAN-11-CVE-2026-31722, ROOT-OS-DEBIAN-12-CVE-2026-31722, ROOT-OS-UBUNTU-2204-CVE-2026-31722, ROOT-OS-UBUNTU-2404-CVE-2026-31722, UBUNTU-CVE-2026-31722

## What is CVE-2026-31722?

CVE-2026-31722 is a medium-severity 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:

usb: gadget: f_rndis: Fix net_device lifecycle with device_move

The net_device is allocated during function instance creation and
registered during the bind phase with the gadget device as its sysfs
parent. When the function unbinds, the parent device is destroyed, but
the net_device survives, resulting in dangling sysfs symlinks:

  console:/ # ls -l /sys/class/net/usb0
  lrwxrwxrwx ... /sys/class/net/usb0 ->
  /sys/devices/platform/.../gadget.0/net/usb0
  console:/ # ls -l /sys/devices/platform/.../gadget.0/net/usb0
  ls: .../gadget.0/net/usb0: No such file or directory

Use device_move() to reparent the net_device between the gadget device
tree and /sys/devices/virtual across bind and unbind cycles. During the
final unbind, calling device_move(NULL) moves the net_device to the
virtual device tree before the gadget device is destroyed. On rebinding,
device_move() reparents the device back under the new gadget, ensuring
proper sysfs topology and power management ordering.

To maintain compatibility with legacy composite drivers (e.g., multi.c),
the borrowed_net flag is used to indicate whether the network device is
shared and pre-registered during the legacy driver's bind phase.

## Which versions are affected by CVE-2026-31722?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31722?

Apply the vendor's patch.

## Is CVE-2026-31722 being exploited?

There is no known exploitation of CVE-2026-31722 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-2026-31722 and fix it if it is affected.

What it is: CVE-2026-31722 is a medium-severity 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-2026-31722 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-2026-31722/ (Markdown: https://insights.sbomify.com/CVE-2026-31722/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31722
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31722
- OSV: https://osv.dev/vulnerability/CVE-2026-31722

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31722/
Summaries are generated and may contain mistakes; the official description above is the record.