# CVE-2026-90364: ACPI: processor: Unregister cpufreq notifier on init failure

> A failure in Linux kernel ACPI processor initialization leaves a cpufreq notifier registered, potentially causing system instability or denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-102984, BELL-CVE-2026-90364, DEBIAN-CVE-2026-90364, GHSA-q82p-xqw2-q8m2, UBUNTU-CVE-2026-90364

## What is CVE-2026-90364?

CVE-2026-90364 is a denial of service vulnerability in Linux, published on 17 Sep 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:

ACPI: processor: Unregister cpufreq notifier on init failure

acpi_processor_driver_init() registers the cpufreq policy notifier before
registering the ACPI processor driver and setting up CPU hotplug state.

If driver_register() or cpuhp_setup_state() fails, the error path only
unregisters the ACPI processor driver and the idle driver. The cpufreq
notifier remains registered even though initialization failed.

Mirror the module exit path on the init failure path and unregister the
cpufreq notifier when it has been registered.

## Which versions are affected by CVE-2026-90364?


## How do I fix CVE-2026-90364?

Apply the vendor's patch.

## Is CVE-2026-90364 being exploited?

There is no known exploitation of CVE-2026-90364 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90364 and fix it if it is affected.

What it is: CVE-2026-90364 is a denial of service vulnerability in Linux, published on 17 Sep 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-2026-90364 in the wild and no public exploit code.

Affected product: Linux. 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-2026-90364/ (Markdown: https://insights.sbomify.com/CVE-2026-90364/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90364
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90364
- OSV: https://osv.dev/vulnerability/CVE-2026-90364

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90364/
Summaries are generated and may contain mistakes; the official description above is the record.