# CVE-2026-89611: ntfs: validate non-resident attribute offsets

> A malicious MFT record can trigger out-of-bounds writes in the Linux kernel NTFS driver, potentially allowing local attackers to execute code or escalate privileges.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-100067, BELL-CVE-2026-89611, DEBIAN-CVE-2026-89611, GHSA-h6x4-53v9-p3rg, UBUNTU-CVE-2026-89611

## What is CVE-2026-89611?

CVE-2026-89611 is a critical memory corruption vulnerability in Linux, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

ntfs: validate non-resident attribute offsets

ntfs_attr_update_meta() shifts the attribute name when converting between
non-sparse and sparse attributes. Converting to sparse also adds the
compressed_size field before the name and mapping pairs, requiring eight
additional bytes in the attribute record.

However, the validator does not check that name_offset is within safe
boundaries for these operations or that the additional space is available.
A malicious MFT record could set name_offset such that:

1. The name is positioned at the very end of a non-sparse attribute.
   Converting to sparse would shift the name forward by 8 bytes,
   writing beyond the attribute boundary.

2. The name overlaps with the mapping pairs, causing corruption during
   conversion.

Add validation to ensure:
- For named attributes, name_offset is within valid bounds
- Name does not extend beyond the attribute or overlap with mapping pairs
- For non-sparse, non-compressed attributes, eight bytes are available
  after mapping_pairs_offset for the compressed_size field

The space check also covers unnamed attributes, for which name_offset = 0
is valid and no name range needs to be checked.

## Which versions are affected by CVE-2026-89611?


## How do I fix CVE-2026-89611?

Apply the vendor's patch.

## Is CVE-2026-89611 being exploited?

There is no known exploitation of CVE-2026-89611 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89611 and fix it if it is affected.

What it is: CVE-2026-89611 is a critical memory corruption vulnerability in Linux, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-89611 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-2026-89611/ (Markdown: https://insights.sbomify.com/CVE-2026-89611/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89611
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89611
- OSV: https://osv.dev/vulnerability/CVE-2026-89611

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89611/
Summaries are generated and may contain mistakes; the official description above is the record.