# CVE-2026-93086: firmware: arm_scmi: Avoid IDR updates while cleaning channels

> A race condition in the Linux kernel SCMI driver can cause a denial of service during channel cleanup.

- **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-102410, BELL-CVE-2026-93086, DEBIAN-CVE-2026-93086, GHSA-w3xq-cq2m-6h87, UBUNTU-CVE-2026-93086

## What is CVE-2026-93086?

CVE-2026-93086 is a 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:

firmware: arm_scmi: Avoid IDR updates while cleaning channels

scmi_cleanup_channels() walks the TX/RX channel IDRs with
idr_for_each() to free transport resources and destroy the dedicated
transport devices before calling idr_destroy().

The destroy callback removed each entry from the same IDR being walked.
That is not needed for this cleanup path, and it is unsafe because
idr_for_each() has not advanced its radix-tree iterator while the
callback is running. Removing the current entry from the callback can
invalidate the iterator state. The callback also cannot be protected by
rcu_read_lock(), because scmi_device_destroy() may sleep.

Leave IDR teardown to the following idr_destroy() call and keep the
callback limited to device destruction.

## Which versions are affected by CVE-2026-93086?


## How do I fix CVE-2026-93086?

Apply the vendor's patch.

## Is CVE-2026-93086 being exploited?

There is no known exploitation of CVE-2026-93086 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93086 and fix it if it is affected.

What it is: CVE-2026-93086 is a 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-2026-93086 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-2026-93086/ (Markdown: https://insights.sbomify.com/CVE-2026-93086/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93086
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93086
- OSV: https://osv.dev/vulnerability/CVE-2026-93086

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93086/
Summaries are generated and may contain mistakes; the official description above is the record.