# CVE-2026-98770: usb: gadget: midi2: Fix the jack descriptor array sizes

> A local attacker with physical access can trigger an out-of-bounds write in the Linux kernel USB MIDI2 gadget driver via configfs, potentially leading to code execution or system crash.

- **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:** 18 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-109337, BELL-CVE-2026-98770, DEBIAN-CVE-2026-98770, GHSA-2cr9-h7x6-p393, UBUNTU-CVE-2026-98770

## What is CVE-2026-98770?

CVE-2026-98770 is a memory corruption vulnerability in Linux, published on 18 Oct 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: Fix the jack descriptor array sizes

The jack in/out descriptor arrays in struct f_midi2_usb_config have
the size of MAX_CABLES, which look reasonable -- but it turned out to
be incorrect.  Namely, the entries for those arrays are added from
both inputs and outputs, hence for each loop cycle, it adds two, ended
up with as twice as the expected size.  This inconsistency may result
in potential OOB when a large number of jacks are set up via configfs,
although the max number of cables (the loop count) is limited to
MAX_CABLES.

For addressing it, correct the jack_ins & jack_outs array sizes to
twice, MAX_CABLES * 2.

## Which versions are affected by CVE-2026-98770?


## How do I fix CVE-2026-98770?

Apply the vendor's patch.

## Is CVE-2026-98770 being exploited?

There is no known exploitation of CVE-2026-98770 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98770 and fix it if it is affected.

What it is: CVE-2026-98770 is a memory corruption vulnerability in Linux, published on 18 Oct 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-2026-98770 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-2026-98770/ (Markdown: https://insights.sbomify.com/CVE-2026-98770/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98770
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98770
- OSV: https://osv.dev/vulnerability/CVE-2026-98770

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98770/
Summaries are generated and may contain mistakes; the official description above is the record.