# CVE-2026-72257: ASoC: qcom: q6apm: fix NULL pointer dereference in graph_callback

> A race condition in the Qualcomm ASoC driver causes a NULL pointer dereference, leading to a kernel crash and denial of service.

- **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-2026-72257, DEBIAN-CVE-2026-72257, GHSA-jf3h-8vwv-gqw3, UBUNTU-CVE-2026-72257

## What is CVE-2026-72257?

CVE-2026-72257 is a 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:

ASoC: qcom: q6apm: fix NULL pointer dereference in graph_callback

When q6apm_free_fragments() is called it frees rx_data.buf/tx_data.buf
and sets them to NULL under graph->lock. A late DSP buffer-done response
can race with this: graph_callback() passes the !graph->ar_graph guard
(not yet NULL), acquires the lock, but then dereferences a now-NULL buf
pointer to read buf[token].phys, crashing at virtual address 0x10.

Add a NULL check for buf inside the mutex-protected section in both the
write-done (DATA_CMD_RSP_WR_SH_MEM_EP_DATA_BUFFER_DONE_V2) and
read-done (DATA_CMD_RSP_RD_SH_MEM_EP_DATA_BUFFER_V2) handlers and bail
out cleanly if buffers have already been freed.

This problem is only shown up recently while apr bus was updated to
process the commands per service rather from single global queue.

## Which versions are affected by CVE-2026-72257?


## How do I fix CVE-2026-72257?

Apply the vendor's patch.

## Is CVE-2026-72257 being exploited?

There is no known exploitation of CVE-2026-72257 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72257 and fix it if it is affected.

What it is: CVE-2026-72257 is a 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-2026-72257 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-2026-72257/ (Markdown: https://insights.sbomify.com/CVE-2026-72257/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72257
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72257
- OSV: https://osv.dev/vulnerability/CVE-2026-72257

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72257/
Summaries are generated and may contain mistakes; the official description above is the record.