# CVE-2024-26981: nilfs2: fix OOB in nilfs_set_de_type

> An out-of-bounds read in the nilfs2 filesystem allows attackers to cause a denial of service or potentially execute code via crafted 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:** 1 May 2024
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2024-26981, DEBIAN-CVE-2024-26981, GHSA-h8c3-hrx9-cf8g, UBUNTU-CVE-2024-26981

## What is CVE-2024-26981?

CVE-2024-26981 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 1 May 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: fix OOB in nilfs_set_de_type

The size of the nilfs_type_by_mode array in the fs/nilfs2/dir.c file is
defined as "S_IFMT >> S_SHIFT", but the nilfs_set_de_type() function,
which uses this array, specifies the index to read from the array in the
same way as "(mode & S_IFMT) >> S_SHIFT".

static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode
 *inode)
{
	umode_t mode = inode->i_mode;

	de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT]; // oob
}

However, when the index is determined this way, an out-of-bounds (OOB)
error occurs by referring to an index that is 1 larger than the array size
when the condition "mode & S_IFMT == S_IFMT" is satisfied.  Therefore, a
patch to resize the nilfs_type_by_mode array should be applied to prevent
OOB errors.

Weakness: CWE-129 (Improper Validation of Array Index)

## Which versions are affected by CVE-2024-26981?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2024-26981?

Apply the vendor's patch.

## Is CVE-2024-26981 being exploited?

There is no known exploitation of CVE-2024-26981 in the wild and no public exploit code.

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- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-26981 and fix it if it is affected.

What it is: CVE-2024-26981 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 1 May 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-2024-26981 in the wild and no public exploit code.

Affected product: Debian Debian 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-2024-26981/ (Markdown: https://insights.sbomify.com/CVE-2024-26981/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-26981
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-26981
- OSV: https://osv.dev/vulnerability/CVE-2024-26981

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-26981/
Summaries are generated and may contain mistakes; the official description above is the record.