# CVE-2026-43076: ocfs2: validate inline data i_size during inode read

> A use-after-free vulnerability in the Linux kernel's OCFS2 filesystem allows attackers to execute code or cause a denial of service via a corrupted filesystem image.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 6 May 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-43076, DEBIAN-CVE-2026-43076, GHSA-w594-5gj3-f9g6, ROOT-OS-DEBIAN-11-CVE-2026-43076, ROOT-OS-DEBIAN-12-CVE-2026-43076, ROOT-OS-UBUNTU-2204-CVE-2026-43076, ROOT-OS-UBUNTU-2404-CVE-2026-43076, UBUNTU-CVE-2026-43076

## What is CVE-2026-43076?

CVE-2026-43076 is a high-severity use after free vulnerability in Linux kernel, published on 6 May 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

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

ocfs2: validate inline data i_size during inode read

When reading an inode from disk, ocfs2_validate_inode_block() performs
various sanity checks but does not validate the size of inline data.  If
the filesystem is corrupted, an inode's i_size can exceed the actual
inline data capacity (id_count).

This causes ocfs2_dir_foreach_blk_id() to iterate beyond the inline data
buffer, triggering a use-after-free when accessing directory entries from
freed memory.

In the syzbot report:
  - i_size was 1099511627576 bytes (~1TB)
  - Actual inline data capacity (id_count) is typically <256 bytes
  - A garbage rec_len (54648) caused ctx->pos to jump out of bounds
  - This triggered a UAF in ocfs2_check_dir_entry()

Fix by adding a validation check in ocfs2_validate_inode_block() to ensure
inodes with inline data have i_size <= id_count.  This catches the
corruption early during inode read and prevents all downstream code from
operating on invalid data.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-43076?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43076?

Apply the vendor's patch.

## Is CVE-2026-43076 being exploited?

There is no known exploitation of CVE-2026-43076 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-2026-43076 and fix it if it is affected.

What it is: CVE-2026-43076 is a high-severity use after free vulnerability in Linux kernel, published on 6 May 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-43076 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-2026-43076/ (Markdown: https://insights.sbomify.com/CVE-2026-43076/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43076
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43076
- OSV: https://osv.dev/vulnerability/CVE-2026-43076

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43076/
Summaries are generated and may contain mistakes; the official description above is the record.