# CVE-2026-68176: tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev

> A local attacker with access to mmiotrace can cause a kernel crash by triggering a NULL pointer dereference when no PCI device is found.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** BELL-CVE-2026-68176, DEBIAN-CVE-2026-68176, GHSA-ghxj-phm3-49fw, UBUNTU-CVE-2026-68176

## What is CVE-2026-68176?

CVE-2026-68176 is a vulnerability in Linux, published on 10 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: Fix mmiotrace possible NULL dereferencing of hiter->dev

If the mmio_pipe_open() fails to find a PCI device, the hiter->dev
will be assigned to NULL. The mmiotrace read() function dereferences the
hiter->dev if hiter exists.

Change the test of the read to not only check hiter being NULL, but also
the hiter->dev before dereferencing it.

## Which versions are affected by CVE-2026-68176?


## How do I fix CVE-2026-68176?

Apply the vendor's patch.

## Is CVE-2026-68176 being exploited?

There is no known exploitation of CVE-2026-68176 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68176 and fix it if it is affected.

What it is: CVE-2026-68176 is a vulnerability in Linux, published on 10 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-2026-68176 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-2026-68176/ (Markdown: https://insights.sbomify.com/CVE-2026-68176/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68176
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68176
- OSV: https://osv.dev/vulnerability/CVE-2026-68176

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68176/
Summaries are generated and may contain mistakes; the official description above is the record.