# CVE-2026-23186: hwmon: (acpi_power_meter) Fix deadlocks related to acpi_power_meter_notify()

> A race condition in the Linux kernel's acpi_power_meter driver can cause deadlocks during device removal, leading to a denial of service.

- **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:** 14 Feb 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-23186, DEBIAN-CVE-2026-23186, GHSA-2m65-7fpj-78p9, UBUNTU-CVE-2026-23186

## What is CVE-2026-23186?

CVE-2026-23186 is a medium-severity vulnerability in Linux kernel, published on 14 Feb 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: (acpi_power_meter) Fix deadlocks related to acpi_power_meter_notify()

The acpi_power_meter driver's .notify() callback function,
acpi_power_meter_notify(), calls hwmon_device_unregister() under a lock
that is also acquired by callbacks in sysfs attributes of the device
being unregistered which is prone to deadlocks between sysfs access and
device removal.

Address this by moving the hwmon device removal in
acpi_power_meter_notify() outside the lock in question, but notice
that doing it alone is not sufficient because two concurrent
METER_NOTIFY_CONFIG notifications may be attempting to remove the
same device at the same time.  To prevent that from happening, add a
new lock serializing the execution of the switch () statement in
acpi_power_meter_notify().  For simplicity, it is a static mutex
which should not be a problem from the performance perspective.

The new lock also allows the hwmon_device_register_with_info()
in acpi_power_meter_notify() to be called outside the inner lock
because it prevents the other notifications handled by that function
from manipulating the "resource" object while the hwmon device based
on it is being registered.  The sending of ACPI netlink messages from
acpi_power_meter_notify() is serialized by the new lock too which
generally helps to ensure that the order of handling firmware
notifications is the same as the order of sending netlink messages
related to them.

In addition, notice that hwmon_device_register_with_info() may fail
in which case resource->hwmon_dev will become an error pointer,
so add checks to avoid attempting to unregister the hwmon device
pointer to by it in that case to acpi_power_meter_notify() and
acpi_power_meter_remove().

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2026-23186?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23186?

Apply the vendor's patch.

## Is CVE-2026-23186 being exploited?

There is no known exploitation of CVE-2026-23186 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-2026-23186 and fix it if it is affected.

What it is: CVE-2026-23186 is a medium-severity vulnerability in Linux kernel, published on 14 Feb 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-2026-23186 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-2026-23186/ (Markdown: https://insights.sbomify.com/CVE-2026-23186/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23186
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23186
- OSV: https://osv.dev/vulnerability/CVE-2026-23186

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23186/
Summaries are generated and may contain mistakes; the official description above is the record.