# CVE-2025-39805: net: macb: fix unregister_netdev call order in macb_remove()

> A kernel warning and potential crash occur when removing a macb network device due to incorrect cleanup order, requiring a patch to fix.

- **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:** 16 Sep 2025
- **Updated:** 11 May 2026
- **Also known as:** AZL-67404, BELL-CVE-2025-39805, DEBIAN-CVE-2025-39805, GHSA-7fr9-7jpw-v2gm, ROOT-OS-DEBIAN-12-CVE-2025-39805, ROOT-OS-DEBIAN-13-CVE-2025-39805, ROOT-OS-UBUNTU-2404-CVE-2025-39805, UBUNTU-CVE-2025-39805

## What is CVE-2025-39805?

CVE-2025-39805 is a medium-severity vulnerability in Linux kernel, published on 16 Sep 2025. 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:

net: macb: fix unregister_netdev call order in macb_remove()

When removing a macb device, the driver calls phy_exit() before
unregister_netdev(). This leads to a WARN from kernfs:

  ------------[ cut here ]------------
  kernfs: can not remove 'attached_dev', no directory
  WARNING: CPU: 1 PID: 27146 at fs/kernfs/dir.c:1683
  Call trace:
    kernfs_remove_by_name_ns+0xd8/0xf0
    sysfs_remove_link+0x24/0x58
    phy_detach+0x5c/0x168
    phy_disconnect+0x4c/0x70
    phylink_disconnect_phy+0x6c/0xc0 [phylink]
    macb_close+0x6c/0x170 [macb]
    ...
    macb_remove+0x60/0x168 [macb]
    platform_remove+0x5c/0x80
    ...

The warning happens because the PHY is being exited while the netdev
is still registered. The correct order is to unregister the netdev
before shutting down the PHY and cleaning up the MDIO bus.

Fix this by moving unregister_netdev() ahead of phy_exit() in
macb_remove().

## Which versions are affected by CVE-2025-39805?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-39805?

Apply the vendor's patch.

## Is CVE-2025-39805 being exploited?

There is no known exploitation of CVE-2025-39805 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-2025-39805 and fix it if it is affected.

What it is: CVE-2025-39805 is a medium-severity vulnerability in Linux kernel, published on 16 Sep 2025. 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-2025-39805 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-2025-39805/ (Markdown: https://insights.sbomify.com/CVE-2025-39805/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39805
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39805
- OSV: https://osv.dev/vulnerability/CVE-2025-39805

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39805/
Summaries are generated and may contain mistakes; the official description above is the record.