# CVE-2024-40951: ocfs2: fix NULL pointer dereference in ocfs2_abort_trigger()

> A NULL pointer dereference in the Linux kernel's OCFS2 filesystem can cause a system crash, requiring a kernel patch to resolve.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 12 Jul 2024
- **Updated:** 11 May 2026
- **Also known as:** AZL-47433, BELL-CVE-2024-40951, DEBIAN-CVE-2024-40951, GHSA-86g8-833h-3hcm, UBUNTU-CVE-2024-40951

## What is CVE-2024-40951?

CVE-2024-40951 is a medium-severity vulnerability in Linux kernel, published on 12 Jul 2024. 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 pointer dereference in ocfs2_abort_trigger()

bdev->bd_super has been removed and commit 8887b94d9322 change the usage
from bdev->bd_super to b_assoc_map->host->i_sb.  Since ocfs2 hasn't set
bh->b_assoc_map, it will trigger NULL pointer dereference when calling
into ocfs2_abort_trigger().

Actually this was pointed out in history, see commit 74e364ad1b13.  But
I've made a mistake when reviewing commit 8887b94d9322 and then
re-introduce this regression.

Since we cannot revive bdev in buffer head, so fix this issue by
initializing all types of ocfs2 triggers when fill super, and then get the
specific ocfs2 trigger from ocfs2_caching_info when access journal.

[joseph.qi@linux.alibaba.com: v2]

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2024-40951?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-40951?

Apply the vendor's patch.

## Is CVE-2024-40951 being exploited?

There is no known exploitation of CVE-2024-40951 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-2024-40951 and fix it if it is affected.

What it is: CVE-2024-40951 is a medium-severity vulnerability in Linux kernel, published on 12 Jul 2024. 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-2024-40951 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-2024-40951/ (Markdown: https://insights.sbomify.com/CVE-2024-40951/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-40951
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-40951
- OSV: https://osv.dev/vulnerability/CVE-2024-40951

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-40951/
Summaries are generated and may contain mistakes; the official description above is the record.