# CVE-2026-93056: usb: gadget: f_uac1_legacy: remove broken string configfs attributes

> A null pointer dereference in the Linux kernel's legacy USB audio gadget driver can cause a system crash when specific configfs attributes are written to.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **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-102638, BELL-CVE-2026-93056, DEBIAN-CVE-2026-93056, GHSA-chwv-5hpv-rv25, UBUNTU-CVE-2026-93056

## What is CVE-2026-93056?

CVE-2026-93056 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:

usb: gadget: f_uac1_legacy: remove broken string configfs attributes

The UAC1_STR_ATTRIBUTE macro defines configfs show/store handlers for
the fn_play, fn_cap, and fn_cntl string options. The store function
contains an inverted null check on the kstrndup() return value.

This means every write attempt returns -ENOMEM on success and
dereferences a NULL pointer on allocation failure. The attributes
have been broken and unused for many years.

Remove the UAC1_STR_ATTRIBUTE macro and the three attributes it
generated. The internal defaults (FILE_PCM_PLAYBACK, FILE_PCM_CAPTURE,
FILE_CONTROL) set in f_audio_alloc_inst() are unaffected.

## Which versions are affected by CVE-2026-93056?


## How do I fix CVE-2026-93056?

Apply the vendor's patch.

## Is CVE-2026-93056 being exploited?

There is no known exploitation of CVE-2026-93056 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93056 and fix it if it is affected.

What it is: CVE-2026-93056 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-2026-93056 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-2026-93056/ (Markdown: https://insights.sbomify.com/CVE-2026-93056/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93056
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93056
- OSV: https://osv.dev/vulnerability/CVE-2026-93056

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93056/
Summaries are generated and may contain mistakes; the official description above is the record.