# CVE-2026-80674: ntfs: validate resident attribute lists and harden the validator

> A crafted resident attribute list in the Linux kernel NTFS driver causes out-of-bounds reads, potentially leading to denial of service or information disclosure.

- **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:** 28 Aug 2026
- **Updated:** 29 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-80674, GHSA-2h39-9r89-9rx3, UBUNTU-CVE-2026-80674

## What is CVE-2026-80674?

CVE-2026-80674 is a critical memory corruption vulnerability in Linux, published on 28 Aug 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 resident attribute lists and harden the validator

A base inode's $ATTRIBUTE_LIST is sanity-checked by load_attribute_list()
only on the non-resident path; ntfs_read_locked_inode() copies a *resident*
attribute list into ni->attr_list with a plain memcpy() and no validation
at all. Every subsequent walk of ni->attr_list --
ntfs_external_attr_find(), ntfs_inode_attach_all_extents() and
ntfs_attrlist_need() -- then trusts the entries are well-formed and reads
attr_list_entry fixed-header fields
(lowest_vcn at offset 8, mft_reference at offset 16, and the name) with
bounds that assume validation already happened. A crafted resident
attribute list therefore reaches those walks unvalidated and can drive
out-of-bounds reads of the attribute-list buffer.

load_attribute_list() itself reads ale->name_offset (offset 7),
ale->mft_reference (offset 16) and the name length under only an
"al < al_start + size" bound, so its own validation loop can over-read the
fixed header of a truncated trailing entry by a few bytes.

Factor the per-entry validation into ntfs_attr_list_entry_is_valid(),
which requires each entry's fixed header (offsetof(struct
attr_list_entry, name)) to be in range before any field is dereferenced,
that ale->length is a multiple of 8 covering the fixed header plus the
name, and that the entry is in use and carries a live MFT reference.
ntfs_attr_list_is_valid() walks the buffer with it and checks the entries
tile it exactly. Use the list validator in load_attribute_list()
(replacing the open-coded loop, closing its own over-read) and on the
resident path in ntfs_read_locked_inode() (which previously skipped
validation entirely); patches 2/3 reuse the per-entry helper at the other
two attribute-list walks.

## Which versions are affected by CVE-2026-80674?


## How do I fix CVE-2026-80674?

Apply the vendor's patch.

## Is CVE-2026-80674 being exploited?

There is no known exploitation of CVE-2026-80674 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80674 and fix it if it is affected.

What it is: CVE-2026-80674 is a critical memory corruption vulnerability in Linux, published on 28 Aug 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-2026-80674 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-2026-80674/ (Markdown: https://insights.sbomify.com/CVE-2026-80674/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80674
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80674
- OSV: https://osv.dev/vulnerability/CVE-2026-80674

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80674/
Summaries are generated and may contain mistakes; the official description above is the record.