# CVE-2026-80689: tracing/mmiotrace: Add NULL check for mmio_trace_array in logging functions

> A NULL pointer dereference in the Linux kernel's mmiotrace logging functions can cause a system crash, requiring a kernel patch.

- **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:** 28 Aug 2026
- **Updated:** 14 Sep 2026
- **Also known as:** AZL-98175, BELL-CVE-2026-80689, DEBIAN-CVE-2026-80689, GHSA-6q77-h2mr-vrm4, UBUNTU-CVE-2026-80689

## What is CVE-2026-80689?

CVE-2026-80689 is a vulnerability in Linux, published on 28 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:

tracing/mmiotrace: Add NULL check for mmio_trace_array in logging functions

mmio_trace_rw() and mmio_trace_mapping() retrieve mmio_trace_array into
tr and pass it to __trace_mmiotrace_rw() and __trace_mmiotrace_map().
If these functions are invoked while mmio_trace_array is NULL (e.g. before
initialization or after disabled), accessing tr->array_buffer.buffer will
result in a NULL pointer dereference crash.

Fix this by adding an explicit NULL check for tr at the beginning of
__trace_mmiotrace_rw() and __trace_mmiotrace_map().

## Which versions are affected by CVE-2026-80689?


## How do I fix CVE-2026-80689?

Apply the vendor's patch.

## Is CVE-2026-80689 being exploited?

There is no known exploitation of CVE-2026-80689 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80689 and fix it if it is affected.

What it is: CVE-2026-80689 is a vulnerability in Linux, published on 28 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-2026-80689 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-2026-80689/ (Markdown: https://insights.sbomify.com/CVE-2026-80689/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80689
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80689
- OSV: https://osv.dev/vulnerability/CVE-2026-80689

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80689/
Summaries are generated and may contain mistakes; the official description above is the record.