# CVE-2026-72163: ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits

> A local attacker can trigger a kernel panic via direct I/O on unwritten extents in OCFS2, causing a 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-2026-72163, DEBIAN-CVE-2026-72163, GHSA-54g6-8m9x-g4c9, UBUNTU-CVE-2026-72163

## What is CVE-2026-72163?

CVE-2026-72163 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:

ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits

[BUG]
A direct write over unwritten extents can panic the kernel in
ocfs2_assure_trans_credits() when the journal aborts during DIO
completion. The crash is a general protection fault from a NULL pointer
dereference.

[CAUSE]
ocfs2_dio_end_io_write() loops over a direct write's unwritten extents,
marking each written under a single journal handle. If the journal
aborts (for example after an I/O error) while the extent tree is being
updated, the handle is left aborted with its transaction pointer
cleared. The extent merge treats that failure as not critical and
reports success, so the loop keeps using the handle.
ocfs2_assure_trans_credits() reads the handle's remaining credits
without first checking whether the handle is aborted, and that read
dereferences the cleared transaction pointer.

[FIX]
A journal abort is recorded in the handle itself, so callers are
expected to test the handle rather than rely on a returned error.
Make ocfs2_assure_trans_credits() do that, as the other ocfs2 journal
helpers already do, and return -EROFS when the handle is aborted.

## Which versions are affected by CVE-2026-72163?


## How do I fix CVE-2026-72163?

Apply the vendor's patch.

## Is CVE-2026-72163 being exploited?

There is no known exploitation of CVE-2026-72163 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72163 and fix it if it is affected.

What it is: CVE-2026-72163 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-2026-72163 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-2026-72163/ (Markdown: https://insights.sbomify.com/CVE-2026-72163/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72163
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72163
- OSV: https://osv.dev/vulnerability/CVE-2026-72163

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72163/
Summaries are generated and may contain mistakes; the official description above is the record.