# CVE-2026-72443: ALSA: usb-audio: Kill MIDI 2.0 URBs before freeing endpoints


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-72443, DEBIAN-CVE-2026-72443, GHSA-mwpv-85xj-7r7v, UBUNTU-CVE-2026-72443

## What is CVE-2026-72443?

CVE-2026-72443 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: Kill MIDI 2.0 URBs before freeing endpoints

MIDI 2.0 input URBs are started during snd_usb_midi_v2_create(). A
later setup failure can still jump to snd_usb_midi_v2_free(), which
currently frees each endpoint and its coherent URB buffers without first
stopping the submitted URBs. A completion can then dereference the
embedded URB context and endpoint state after they have been freed, or
try to resubmit from the stale endpoint.

This was observed as a KASAN slab-use-after-free in
input_urb_complete().

The buggy scenario involves two paths, with each column showing the order
within that path:

probe error path:                         USB completion path:
1. start_input_streams() submits          1. The HCD still owns a
   input URBs.                               submitted input URB.
2. A later setup helper returns           2. input_urb_complete() runs
   an error.                                 with urb->context in ep.
3. snd_usb_midi_v2_free() frees           3. The completion reads ep
   endpoint storage and URB buffers.         state and can requeue URBs.

Make the endpoint destructor follow the same teardown ordering used for
disconnect when the endpoint has not already been disconnected: publish
ep->disconnected, kill the URBs synchronously, and drain the endpoint
before freeing URB buffers and endpoint storage. The guard avoids
repeating the stop sequence after the normal
snd_usb_midi_v2_disconnect_all() path, while still synchronizing the
direct MIDI 2.0 create-error free path.

Validation reproduced this kernel report:
BUG: KASAN: slab-use-after-free in input_urb_complete+0x37/0x1b0
Workqueue: usb_hub_wq hub_event
RIP: 0010:_raw_spin_unlock_irq+0x2e/0x50
Read of size 8
Call trace:
  dump_stack_lvl+0x77/0xb0
  print_report+0xce/0x5f0
  input_urb_complete+0x37/0x1b0 (sound/usb/midi2.c:186)
  srso_alias_return_thunk+0x5/0xfbef5
  __virt_addr_valid+0x19f/0x330
  kasan_report+0xe0/0x110
  __usb_hcd_giveback_urb+0x112/0x1d0
  dummy_timer+0xaaa/0x19a0
  lock_is_held_type+0x9a/0x110
  __lock_acquire+0x467/0x28b0
  mark_held_locks+0x40/0x70
  _raw_spin_unlock_irqrestore+0x44/0x60
  lockdep_hardirqs_on_prepare+0xbb/0x1a0
  __hrtimer_run_queues+0x101/0x520
  hrtimer_run_softirq+0xd0/0x130
  handle_softirqs+0x15b/0x670
  __irq_exit_rcu+0xd0/0x170
  irq_exit_rcu+0xe/0x20
  sysvec_apic_timer_interrupt+0x6c/0x80
  asm_sysvec_apic_timer_interrupt+0x1a/0x20

## Which versions are affected by CVE-2026-72443?


## How do I fix CVE-2026-72443?

Upgrade to a fixed version.

## Is CVE-2026-72443 being exploited?

There is no known exploitation of CVE-2026-72443 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72443 and fix it if it is affected.

What it is: CVE-2026-72443 is a vulnerability in Linux, published on 15 Aug 2026. 
Exploitation: There is no known exploitation of CVE-2026-72443 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-2026-72443/ (Markdown: https://insights.sbomify.com/CVE-2026-72443/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72443
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72443
- OSV: https://osv.dev/vulnerability/CVE-2026-72443

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72443/
Summaries are generated and may contain mistakes; the official description above is the record.