# CVE-2025-38110: net/mdiobus: Fix potential out-of-bounds clause 45 read/write access

> A local attacker can trigger out-of-bounds read/write access in the Linux kernel's mdiobus subsystem via ioctl, potentially leading to memory corruption or information disclosure.

- **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:** 3 Jul 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-64586, BELL-CVE-2025-38110, DEBIAN-CVE-2025-38110, GHSA-q3p7-pjx2-7hjq, ROOT-OS-UBUNTU-2404-CVE-2025-38110, UBUNTU-CVE-2025-38110

## What is CVE-2025-38110?

CVE-2025-38110 is a high-severity memory corruption vulnerability in Linux kernel, published on 3 Jul 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/mdiobus: Fix potential out-of-bounds clause 45 read/write access

When using publicly available tools like 'mdio-tools' to read/write data
from/to network interface and its PHY via C45 (clause 45) mdiobus,
there is no verification of parameters passed to the ioctl and
it accepts any mdio address.
Currently there is support for 32 addresses in kernel via PHY_MAX_ADDR define,
but it is possible to pass higher value than that via ioctl.
While read/write operation should generally fail in this case,
mdiobus provides stats array, where wrong address may allow out-of-bounds
read/write.

Fix that by adding address verification before C45 read/write operation.
While this excludes this access from any statistics, it improves security of
read/write operation.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2025-38110?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-38110?

Apply the vendor's patch.

## Is CVE-2025-38110 being exploited?

There is no known exploitation of CVE-2025-38110 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-2025-38110 and fix it if it is affected.

What it is: CVE-2025-38110 is a high-severity memory corruption vulnerability in Linux kernel, published on 3 Jul 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-2025-38110 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-2025-38110/ (Markdown: https://insights.sbomify.com/CVE-2025-38110/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38110
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38110
- OSV: https://osv.dev/vulnerability/CVE-2025-38110

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38110/
Summaries are generated and may contain mistakes; the official description above is the record.