# CVE-2026-72162: ocfs2: fix UBSAN array-index-out-of-bounds in ocfs2_sum_rightmost_rec

> A missing bounds check in the Linux kernel OCFS2 filesystem allows a local attacker to cause a system crash via a crafted disk image.

- **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
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** BELL-CVE-2026-72162, DEBIAN-CVE-2026-72162, GHSA-w4g7-33m6-26g5, UBUNTU-CVE-2026-72162

## What is CVE-2026-72162?

CVE-2026-72162 is a high-severity 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 UBSAN array-index-out-of-bounds in ocfs2_sum_rightmost_rec

[BUG]
On-disk corruption setting l_next_free_rec to 0 in an inode's embedded
extent list triggers a UBSAN panic on the next write to that file.

[CAUSE]
ocfs2_sum_rightmost_rec() computes
i = le16_to_cpu(el->l_next_free_rec) - 1
and accesses el->l_recs[i] without validating i. When l_next_free_rec
is 0, i becomes -1; when l_next_free_rec exceeds l_count, i falls
past the end of the array. Either case violates the
__counted_by_le(l_count) annotation on l_recs[] and triggers UBSAN.

[FIX]
Validate the inode's embedded extent list when the inode is read, in
ocfs2_validate_inode_block(): l_count must be non-zero and no larger
than the inode block can hold, and l_next_free_rec must not exceed
l_count. A corrupt list is rejected at read time, before the b-tree
code can index l_recs[] out of bounds.

## Which versions are affected by CVE-2026-72162?


## How do I fix CVE-2026-72162?

Apply the vendor's patch.

## Is CVE-2026-72162 being exploited?

There is no known exploitation of CVE-2026-72162 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72162 and fix it if it is affected.

What it is: CVE-2026-72162 is a high-severity 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-2026-72162 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-2026-72162/ (Markdown: https://insights.sbomify.com/CVE-2026-72162/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72162
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72162
- OSV: https://osv.dev/vulnerability/CVE-2026-72162

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72162/
Summaries are generated and may contain mistakes; the official description above is the record.