# CVE-2024-42104: nilfs2: add missing check for inode numbers on directory entries

> A use-after-free vulnerability in the nilfs2 filesystem allows attackers to cause a kernel crash or potentially execute code via corrupted filesystem images.

- **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:** 30 Jul 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2024-42104, DEBIAN-CVE-2024-42104, GHSA-7hm7-x364-qr2m, UBUNTU-CVE-2024-42104

## What is CVE-2024-42104?

CVE-2024-42104 is a high-severity use after free vulnerability in Linux kernel, published on 30 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:

nilfs2: add missing check for inode numbers on directory entries

Syzbot reported that mounting and unmounting a specific pattern of
corrupted nilfs2 filesystem images causes a use-after-free of metadata
file inodes, which triggers a kernel bug in lru_add_fn().

As Jan Kara pointed out, this is because the link count of a metadata file
gets corrupted to 0, and nilfs_evict_inode(), which is called from iput(),
tries to delete that inode (ifile inode in this case).

The inconsistency occurs because directories containing the inode numbers
of these metadata files that should not be visible in the namespace are
read without checking.

Fix this issue by treating the inode numbers of these internal files as
errors in the sanity check helper when reading directory folios/pages.

Also thanks to Hillf Danton and Matthew Wilcox for their initial mm-layer
analysis.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2024-42104?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-42104?

Apply the vendor's patch.

## Is CVE-2024-42104 being exploited?

There is no known exploitation of CVE-2024-42104 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-2024-42104 and fix it if it is affected.

What it is: CVE-2024-42104 is a high-severity use after free vulnerability in Linux kernel, published on 30 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-2024-42104 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-2024-42104/ (Markdown: https://insights.sbomify.com/CVE-2024-42104/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-42104
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-42104
- OSV: https://osv.dev/vulnerability/CVE-2024-42104

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-42104/
Summaries are generated and may contain mistakes; the official description above is the record.