# CVE-2026-89623: HID: mcp2221: stop device IO before hid_hw_stop

> A race condition in the Linux kernel MCP2221 HID driver allows use-after-free during device removal, potentially enabling local privilege escalation or code execution.

- **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:** 11 Sep 2026
- **Updated:** 24 Oct 2026
- **Also known as:** AZL-100487, BELL-CVE-2026-89623, DEBIAN-CVE-2026-89623, GHSA-p59v-m859-4ppq, UBUNTU-CVE-2026-89623

## What is CVE-2026-89623?

CVE-2026-89623 is an use after free vulnerability in Linux, published on 11 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:

HID: mcp2221: stop device IO before hid_hw_stop

Quiesce device IO at the start of the devm cleanup callback
mcp2221_hid_unregister() so that incoming HID reports cannot race with
hardware teardown during probe failure or device removal, addressing a
potential use-after-free.

Guard the call to hid_device_io_stop() with io_started. On normal
removal hid_device_remove() has already cleared io_started before the
devres group is released, so an unconditional call would otherwise hit
the !io_started path and emit a spurious "io already stopped" warning
on every removal. The guard preserves the probe-failure balancing,
where io_started is still set after hid_device_io_start(), while
staying silent on the normal removal path.

## Which versions are affected by CVE-2026-89623?


## How do I fix CVE-2026-89623?

Apply the vendor's patch.

## Is CVE-2026-89623 being exploited?

There is no known exploitation of CVE-2026-89623 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89623 and fix it if it is affected.

What it is: CVE-2026-89623 is an use after free vulnerability in Linux, published on 11 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-2026-89623 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-2026-89623/ (Markdown: https://insights.sbomify.com/CVE-2026-89623/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89623
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89623
- OSV: https://osv.dev/vulnerability/CVE-2026-89623

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89623/
Summaries are generated and may contain mistakes; the official description above is the record.