# CVE-2026-43075: ocfs2: fix out-of-bounds write in ocfs2_write_end_inline

> An out-of-bounds write in the OCFS2 filesystem allows attackers with local access to mount a corrupted image to execute arbitrary code or escalate privileges.

- **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:** 6 May 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-43075, DEBIAN-CVE-2026-43075, GHSA-v76q-g5wv-jjw6, ROOT-OS-DEBIAN-11-CVE-2026-43075, ROOT-OS-DEBIAN-12-CVE-2026-43075, ROOT-OS-UBUNTU-2204-CVE-2026-43075, ROOT-OS-UBUNTU-2404-CVE-2026-43075, UBUNTU-CVE-2026-43075

## What is CVE-2026-43075?

CVE-2026-43075 is a high-severity memory corruption vulnerability in Linux kernel, published on 6 May 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 out-of-bounds write in ocfs2_write_end_inline

KASAN reports a use-after-free write of 4086 bytes in
ocfs2_write_end_inline, called from ocfs2_write_end_nolock during a
copy_file_range splice fallback on a corrupted ocfs2 filesystem mounted on
a loop device.  The actual bug is an out-of-bounds write past the inode
block buffer, not a true use-after-free.  The write overflows into an
adjacent freed page, which KASAN reports as UAF.

The root cause is that ocfs2_try_to_write_inline_data trusts the on-disk
id_count field to determine whether a write fits in inline data.  On a
corrupted filesystem, id_count can exceed the physical maximum inline data
capacity, causing writes to overflow the inode block buffer.

Call trace (crash path):

   vfs_copy_file_range (fs/read_write.c:1634)
     do_splice_direct
       splice_direct_to_actor
         iter_file_splice_write
           ocfs2_file_write_iter
             generic_perform_write
               ocfs2_write_end
                 ocfs2_write_end_nolock (fs/ocfs2/aops.c:1949)
                   ocfs2_write_end_inline (fs/ocfs2/aops.c:1915)
                     memcpy_from_folio     <-- KASAN: write OOB

So add id_count upper bound check in ocfs2_validate_inode_block() to
alongside the existing i_size check to fix it.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-43075?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43075?

Apply the vendor's patch.

## Is CVE-2026-43075 being exploited?

There is no known exploitation of CVE-2026-43075 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43075 and fix it if it is affected.

What it is: CVE-2026-43075 is a high-severity memory corruption vulnerability in Linux kernel, published on 6 May 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-2026-43075 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-43075/ (Markdown: https://insights.sbomify.com/CVE-2026-43075/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43075
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43075
- OSV: https://osv.dev/vulnerability/CVE-2026-43075

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43075/
Summaries are generated and may contain mistakes; the official description above is the record.