# CVE-2023-53861: ext4: correct grp validation in ext4_mb_good_group

> A null pointer dereference in the Linux kernel ext4 filesystem allows local attackers to cause a system crash via corrupted group data.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Dec 2025
- **Updated:** 23 May 2026
- **Also known as:** BELL-CVE-2023-53861, DEBIAN-CVE-2023-53861, GHSA-9chw-7w35-c7qm, UBUNTU-CVE-2023-53861

## What is CVE-2023-53861?

CVE-2023-53861 is a vulnerability in Linux, published on 9 Dec 2025. 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:

ext4: correct grp validation in ext4_mb_good_group

Group corruption check will access memory of grp and will trigger kernel
crash if grp is NULL. So do NULL check before corruption check.

## Which versions are affected by CVE-2023-53861?


## How do I fix CVE-2023-53861?

Apply the vendor's patch.

## Is CVE-2023-53861 being exploited?

There is no known exploitation of CVE-2023-53861 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-53861 and fix it if it is affected.

What it is: CVE-2023-53861 is a vulnerability in Linux, published on 9 Dec 2025. 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-2023-53861 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-2023-53861/ (Markdown: https://insights.sbomify.com/CVE-2023-53861/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53861
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53861
- OSV: https://osv.dev/vulnerability/CVE-2023-53861

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53861/
Summaries are generated and may contain mistakes; the official description above is the record.