# CVE-2026-72164: ocfs2: avoid moving extents to occupied clusters


- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-72164, DEBIAN-CVE-2026-72164, GHSA-5r4j-cfqp-hv7w, UBUNTU-CVE-2026-72164

## What is CVE-2026-72164?

CVE-2026-72164 is a high-severity vulnerability in Linux, published on 15 Aug 2026. 

### Official description

In the Linux kernel, the following vulnerability has been resolved:

ocfs2: avoid moving extents to occupied clusters

For non-auto OCFS2_IOC_MOVE_EXT operations, userspace supplies a physical
me_goal.  ocfs2_move_extent() initializes new_phys_cpos from that goal and
expects ocfs2_probe_alloc_group() to replace it with a free run in the
target block group.

The probe currently leaves *phys_cpos unchanged if the scan reaches the
end of the group without finding a free run.  An occupied goal at the last
bit can therefore survive the probe and be passed to
__ocfs2_move_extent(), which copies file data into a cluster still owned
by another inode before the bitmap is updated.

When the probe does find a free run, it also subtracts move_len from the
ending bit.  The start of an N-bit run ending at i is i - N + 1, so the
current calculation can report the bit immediately before the free run.

Clear *phys_cpos before scanning and use the correct free-run start. 
Callers already treat a zero result as -ENOSPC, so failed probes no longer
continue with an occupied caller-controlled goal.

## Which versions are affected by CVE-2026-72164?


## How do I fix CVE-2026-72164?

Upgrade to a fixed version.

## Is CVE-2026-72164 being exploited?

There is no known exploitation of CVE-2026-72164 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72164 and fix it if it is affected.

What it is: CVE-2026-72164 is a high-severity vulnerability in Linux, published on 15 Aug 2026. 
Exploitation: There is no known exploitation of CVE-2026-72164 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-2026-72164/ (Markdown: https://insights.sbomify.com/CVE-2026-72164/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72164
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72164
- OSV: https://osv.dev/vulnerability/CVE-2026-72164

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72164/
Summaries are generated and may contain mistakes; the official description above is the record.