# CVE-2026-89735: usb: gadget: midi2: remove default configfs groups on teardown

> A memory leak in the Linux kernel USB MIDI2 gadget driver can lead to resource exhaustion and 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:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-100608, BELL-CVE-2026-89735, DEBIAN-CVE-2026-89735, GHSA-c38q-5hmw-mm46, UBUNTU-CVE-2026-89735

## What is CVE-2026-89735?

CVE-2026-89735 is a memory corruption 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:

usb: gadget: midi2: remove default configfs groups on teardown

f_midi2_alloc_inst() creates default configfs child groups for the
default endpoint and default block using configfs_add_default_group(),
setting their internal refcount to 1.

However, during function teardown in f_midi2_free_inst() or EP cleanup
in f_midi2_ep_opts_release(), configfs_remove_default_groups() is
never called, therefore never dropping the refcount and leaking struct
f_midi2_ep_opts and f_midi2_block_opts.

Add the missing configfs_remove_default_groups() in the afformentioned
functions to free the structs properly.

## Which versions are affected by CVE-2026-89735?


## How do I fix CVE-2026-89735?

Apply the vendor's patch.

## Is CVE-2026-89735 being exploited?

There is no known exploitation of CVE-2026-89735 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89735 and fix it if it is affected.

What it is: CVE-2026-89735 is a memory corruption 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-2026-89735 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-2026-89735/ (Markdown: https://insights.sbomify.com/CVE-2026-89735/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89735
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89735
- OSV: https://osv.dev/vulnerability/CVE-2026-89735

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89735/
Summaries are generated and may contain mistakes; the official description above is the record.