# CVE-2026-97437: ntfs3: fix out-of-bounds read in ntfs_dir_emit() and hdr_find_e()

> A crafted NTFS image triggers an out-of-bounds read in the Linux kernel, potentially causing a crash or leaking memory contents.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/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:** 24 Sep 2026
- **Updated:** 3 Oct 2026
- **Also known as:** AZL-103955, BELL-CVE-2026-97437, DEBIAN-CVE-2026-97437, GHSA-fpf4-vw37-hxfh, UBUNTU-CVE-2026-97437

## What is CVE-2026-97437?

CVE-2026-97437 is a high-severity memory corruption vulnerability in Linux, published on 24 Sep 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:

ntfs3: fix out-of-bounds read in ntfs_dir_emit() and hdr_find_e()

The bounds check in ntfs_dir_emit() compares fname->name_len (a
character count) against e->size (a byte count) without accounting
for the 2-byte-per-character UTF-16LE encoding or the ATTR_FILE_NAME
header size:

  if (fname->name_len + sizeof(struct NTFS_DE) > le16_to_cpu(e->size))

This computes: name_len + 16 > e_size

The correct check must account for the ATTR_FILE_NAME header (66 bytes
before the name) and the UTF-16LE character size (2 bytes each):

  sizeof(NTFS_DE) + offsetof(ATTR_FILE_NAME, name) +
  name_len * sizeof(short) > e_size

Which computes: 16 + 66 + name_len * 2 > e_size

The correct calculation already exists as fname_full_size() in ntfs.h
and is used in cmp_fnames(), namei.c, and fslog.c, but was not used
in the readdir path.

A crafted NTFS image with an index entry containing a small e->size
but large fname->name_len bypasses the current check, causing
ntfs_utf16_to_nls() to read past the entry boundary.

Additionally, add a key_size validation in hdr_find_e() to ensure the
declared key_size does not exceed the available entry data, preventing
comparison functions from reading past entry boundaries on the lookup
path.

## Which versions are affected by CVE-2026-97437?


## How do I fix CVE-2026-97437?

Apply the vendor's patch.

## Is CVE-2026-97437 being exploited?

There is no known exploitation of CVE-2026-97437 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97437 and fix it if it is affected.

What it is: CVE-2026-97437 is a high-severity memory corruption vulnerability in Linux, published on 24 Sep 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-2026-97437 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-2026-97437/ (Markdown: https://insights.sbomify.com/CVE-2026-97437/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97437
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97437
- OSV: https://osv.dev/vulnerability/CVE-2026-97437

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97437/
Summaries are generated and may contain mistakes; the official description above is the record.