# CVE-2026-72486: mailbox: mtk-adsp: fix UAF during device teardown

> A use-after-free in the Linux kernel mtk-adsp mailbox driver allows local attackers to cause a system crash or potentially execute code during device teardown.

- **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:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-72486, DEBIAN-CVE-2026-72486, GHSA-7xg7-8g6q-847f, UBUNTU-CVE-2026-72486

## What is CVE-2026-72486?

CVE-2026-72486 is an use after free vulnerability in Linux, published on 15 Aug 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:

mailbox: mtk-adsp: fix UAF during device teardown

When the SOF audio driver fails to initialize (e.g. firmware boot
timeout), its devres unwind frees the snd_sof_dev object that the
mailbox client (mtk-adsp-ipc) reaches via chan->cl->rx_callback.
The mtk-adsp-mailbox shutdown clears the mailbox command registers
but leaves the IRQ line unmasked, so a late interrupt can still
queue a threaded handler after mbox_free_channel() had cleared
chan->cl, and mbox_chan_received_data() would then trigger UAF:

  BUG: KASAN: slab-use-after-free in sof_ipc3_validate_fw_version
   sof_ipc3_validate_fw_version
   sof_ipc3_do_rx_work
   sof_ipc3_rx_msg
   mt8196_dsp_handle_request
   mtk_adsp_ipc_recv
   mbox_chan_received_data
   mtk_adsp_mbox_isr
   irq_thread_fn
  Freed by task ...:
   kfree
   devres_release_all
   really_probe
   ... (sof-audio-of-mt8196 probe failure)

The crash was observed roughly three seconds after the failed probe.

disable_irq() in shutdown and enable_irq() in startup. disable_irq()
also waits for any in-flight interrupts, so by the time
mbox_free_channel() proceeds to clear chan->cl no rx_callback can run.

In addition, request the IRQ with IRQF_NO_AUTOEN so it stays masked
between probe and the first client bind — otherwise an early interrupt
can crash on chan->cl == NULL in mbox_chan_received_data().

## Which versions are affected by CVE-2026-72486?


## How do I fix CVE-2026-72486?

Apply the vendor's patch.

## Is CVE-2026-72486 being exploited?

There is no known exploitation of CVE-2026-72486 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72486 and fix it if it is affected.

What it is: CVE-2026-72486 is an use after free vulnerability in Linux, published on 15 Aug 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-2026-72486 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-2026-72486/ (Markdown: https://insights.sbomify.com/CVE-2026-72486/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72486
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72486
- OSV: https://osv.dev/vulnerability/CVE-2026-72486

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72486/
Summaries are generated and may contain mistakes; the official description above is the record.