# CVE-2026-64038: hwmon: (lm90) Stop work before releasing hwmon device

> A use-after-free vulnerability in the Linux kernel lm90 driver allows attackers to cause a denial of service or potentially execute code during device unbinding.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:L/AC:H/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:** 19 Jul 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-92718, BELL-CVE-2026-64038, DEBIAN-CVE-2026-64038, GHSA-35qx-2fp8-64h3, ROOT-OS-DEBIAN-12-CVE-2026-64038, UBUNTU-CVE-2026-64038

## What is CVE-2026-64038?

CVE-2026-64038 is a medium-severity use after free vulnerability in Linux kernel, published on 19 Jul 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:

hwmon: (lm90) Stop work before releasing hwmon device

Sashiko reports:

In lm90_probe(), the devm action to cancel the alert_work and report_work
(lm90_restore_conf) is registered in lm90_init_client() before
devm_hwmon_device_register_with_info() is called.

Because devm executes cleanup actions in reverse order during module
unbind or probe failure, the hwmon device is unregistered and freed first.

If lm90_alert_work() or lm90_report_alarms() runs in the window between
the hwmon device being freed and the delayed works being cancelled,
lm90_update_alarms() will dereference the freed data->hwmon_dev here.

Fix the problem by canceling the workers separately after registering
the hwmon device and before registering the interrupt handler. This ensures
that the workers are canceled after interrupts are disabled and before
the hwmon device is released. Add "shutdown" flag to indicate that device
shutdown is in progress to prevent workers from being re-armed.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-64038?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64038?

Apply the vendor's patch.

## Is CVE-2026-64038 being exploited?

There is no known exploitation of CVE-2026-64038 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-2026-64038 and fix it if it is affected.

What it is: CVE-2026-64038 is a medium-severity use after free vulnerability in Linux kernel, published on 19 Jul 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-2026-64038 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-2026-64038/ (Markdown: https://insights.sbomify.com/CVE-2026-64038/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64038
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64038
- OSV: https://osv.dev/vulnerability/CVE-2026-64038

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64038/
Summaries are generated and may contain mistakes; the official description above is the record.