# CVE-2026-74501: ALSA: usb-audio: fix use-after-free in ump_to_endpoint()


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** AZL-96105, BELL-CVE-2026-74501, DEBIAN-CVE-2026-74501, GHSA-jc2g-jx97-4cg9, UBUNTU-CVE-2026-74501

## What is CVE-2026-74501?

CVE-2026-74501 is a vulnerability in Linux, published on 15 Aug 2026. 

### Official description

In the Linux kernel, the following vulnerability has been resolved:

ALSA: usb-audio: fix use-after-free in ump_to_endpoint()

create_midi2_ump() registers a card-owned snd_ump_endpoint and stores a
back-pointer to its per-interface snd_usb_midi2_ump object in
ump->private_data, but it never installs an ump->private_free hook and
never clears that pointer.

If a later step of snd_usb_midi_v2_create() fails, its error path calls
free_all_midi2_umps(), which kfree()s the snd_usb_midi2_ump object while
the already-registered endpoint keeps pointing at it.  The created
/dev/snd/umpC*D* node stays exposed, so the first operation of any UMP
open, ump_to_endpoint(), dereferences the dangling ump->private_data and
reads rmidi->eps[dir] out of freed memory.

A malicious USB MIDI 2.0 device that makes creation fail after the
endpoint is registered can thus trigger a slab use-after-free read on a
subsequent open of the UMP node.

Clear the endpoint's back-pointer before freeing the object, and let
ump_to_endpoint() tolerate a NULL private_data so the open/close/trigger
callbacks fail cleanly (their callers already handle a NULL endpoint)
instead of dereferencing a stale pointer.

Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>

## Which versions are affected by CVE-2026-74501?


## How do I fix CVE-2026-74501?

Upgrade to a fixed version.

## Is CVE-2026-74501 being exploited?

There is no known exploitation of CVE-2026-74501 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74501 and fix it if it is affected.

What it is: CVE-2026-74501 is a vulnerability in Linux, published on 15 Aug 2026. 
Exploitation: There is no known exploitation of CVE-2026-74501 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-2026-74501/ (Markdown: https://insights.sbomify.com/CVE-2026-74501/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74501
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74501
- OSV: https://osv.dev/vulnerability/CVE-2026-74501

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74501/
Summaries are generated and may contain mistakes; the official description above is the record.