# CVE-2026-64067: netfs: Fix missing barriers when accessing stream->subrequests locklessly

> A race condition in the Linux kernel netfs subsystem due to missing memory barriers could lead to undefined behavior or crashes.

- **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:** 19 Jul 2026
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2026-64067, DEBIAN-CVE-2026-64067, GHSA-f3mp-m5hm-h688, ROOT-OS-DEBIAN-13-CVE-2026-64067, UBUNTU-CVE-2026-64067

## What is CVE-2026-64067?

CVE-2026-64067 is a critical vulnerability in Linux kernel, published on 19 Jul 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:

netfs: Fix missing barriers when accessing stream->subrequests locklessly

The list of subrequests attached to stream->subrequests is accessed without
locks by netfs_collect_read_results() and netfs_collect_write_results(),
and then they access subreq->flags without taking a barrier after getting
the subreq pointer from the list.  Relatedly, the functions that build the
list don't use any sort of write barrier when constructing the list to make
sure that the NETFS_SREQ_IN_PROGRESS flag is perceived to be set first if
no lock is taken.

Fix this by:

 (1) Add a new list_add_tail_release() function that uses a release barrier
     to set the pointer to the new member of the list.

 (2) Add a new list_first_entry_or_null_acquire() function that uses an
     acquire barrier to read the pointer to the first member in a list (or
     return NULL).

 (3) Use list_add_tail_release() when adding a subreq to ->subrequests.

 (4) Use list_first_entry_or_null_acquire() when initially accessing the
     front of the list (when an item is removed, the pointer to the new
     front iterm is obtained under the same lock).

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2026-64067?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64067?

Apply the vendor's patch.

## Is CVE-2026-64067 being exploited?

There is no known exploitation of CVE-2026-64067 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-2026-64067 and fix it if it is affected.

What it is: CVE-2026-64067 is a critical vulnerability in Linux kernel, published on 19 Jul 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-2026-64067 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-2026-64067/ (Markdown: https://insights.sbomify.com/CVE-2026-64067/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64067
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64067
- OSV: https://osv.dev/vulnerability/CVE-2026-64067

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64067/
Summaries are generated and may contain mistakes; the official description above is the record.