# CVE-2026-64213: hwmon: (lm90) Add lock protection to lm90_alert

> A race condition in the Linux kernel lm90 driver can cause an interrupt storm and denial of service when concurrent sysfs writes and hardware alerts occur.

- **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:** 24 Jul 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-93338, BELL-CVE-2026-64213, DEBIAN-CVE-2026-64213, GHSA-mf77-wwf7-m2ff, ROOT-OS-UBUNTU-2204-CVE-2026-64213, UBUNTU-CVE-2026-64213

## What is CVE-2026-64213?

CVE-2026-64213 is a medium-severity vulnerability in Linux kernel, published on 24 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) Add lock protection to lm90_alert

Sashiko reports:

lm90_alert() executes in the smbus alert context and calls
lm90_update_confreg() to disable the hardware alert line, without
acquiring hwmon_lock.

Concurrently, sysfs write operations (such as lm90_write_convrate) hold
the hwmon_lock, temporarily modify data->config, and then restore it.

If an alert interrupt occurs concurrently with a sysfs write, the sysfs
path will overwrite the alert handler's modifications to data->config
and the hardware register.

This unintentionally re-enables the hardware alert line while the alarm is
still active, causing an interrupt storm.

Add the missing lock to lm90_alert() to solve the problem.

## Which versions are affected by CVE-2026-64213?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64213?

Apply the vendor's patch.

## Is CVE-2026-64213 being exploited?

There is no known exploitation of CVE-2026-64213 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-2026-64213 and fix it if it is affected.

What it is: CVE-2026-64213 is a medium-severity vulnerability in Linux kernel, published on 24 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-2026-64213 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-2026-64213/ (Markdown: https://insights.sbomify.com/CVE-2026-64213/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64213
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64213
- OSV: https://osv.dev/vulnerability/CVE-2026-64213

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64213/
Summaries are generated and may contain mistakes; the official description above is the record.