# CVE-2026-93091: firmware: arm_scmi: Quiesce notifications before teardown

> A use-after-free vulnerability in the Linux kernel's SCMI driver allows local attackers to cause denial of service or execute code during device teardown.

- **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-102393, BELL-CVE-2026-93091, DEBIAN-CVE-2026-93091, GHSA-634x-xgvq-4p3j, UBUNTU-CVE-2026-93091

## What is CVE-2026-93091?

CVE-2026-93091 is an use after free 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: Quiesce notifications before teardown

scmi_notification_exit() clears and releases the notification instance,
but transport callbacks can still deliver incoming notifications until
the TX/RX channels are freed. During remove, an RX interrupt in that
window can enter scmi_notify() while notification state is being torn
down and then dereference freed memory. The same ordering exists on the
probe error path after notification initialization.

The notification late-init worker has a separate lifetime issue: protocol
event registration queues ni->init_work on the system workqueue, so
destroying ni->notify_wq does not drain that work. If the devres group is
released while init_work is still pending or running, the late-init worker
can dereference the freed notification instance.

Quiesce the notification core before TX/RX channels are torn down, then
clean up the channels before releasing the notification core resources.
Use disable_work_sync() so future late-init queueing is rejected and any
already queued or running late-init work has completed before channel
teardown starts.

## Which versions are affected by CVE-2026-93091?


## How do I fix CVE-2026-93091?

Apply the vendor's patch.

## Is CVE-2026-93091 being exploited?

There is no known exploitation of CVE-2026-93091 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93091 and fix it if it is affected.

What it is: CVE-2026-93091 is an use after free 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-2026-93091 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-2026-93091/ (Markdown: https://insights.sbomify.com/CVE-2026-93091/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93091
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93091
- OSV: https://osv.dev/vulnerability/CVE-2026-93091

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93091/
Summaries are generated and may contain mistakes; the official description above is the record.