# CVE-2026-72366: netfs: Fix netfs_create_write_req() to handle async cache object creation

> A logic error in the Linux kernel netfs subsystem could skip cache operations during async creation, potentially affecting performance or consistency.

- **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:** 15 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** BELL-CVE-2026-72366, DEBIAN-CVE-2026-72366, GHSA-8q2x-69cw-5m48, UBUNTU-CVE-2026-72366

## What is CVE-2026-72366?

CVE-2026-72366 is a critical vulnerability in Linux, published on 15 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:

netfs: Fix netfs_create_write_req() to handle async cache object creation

netfs_create_write_req() will skip caching if the fscache cookie is
disabled, but this is a problem because async cache object creation might
not have got far enough yet that has been enabled - thereby causing the
call to fscache_begin_write_operation() to be skipped.

Fix this by removing the checks on the cookie and delegating this to
fscache_begin_write_operation().

## Which versions are affected by CVE-2026-72366?


## How do I fix CVE-2026-72366?

Apply the vendor's patch.

## Is CVE-2026-72366 being exploited?

There is no known exploitation of CVE-2026-72366 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72366 and fix it if it is affected.

What it is: CVE-2026-72366 is a critical vulnerability in Linux, published on 15 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-2026-72366 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-2026-72366/ (Markdown: https://insights.sbomify.com/CVE-2026-72366/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72366
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72366
- OSV: https://osv.dev/vulnerability/CVE-2026-72366

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72366/
Summaries are generated and may contain mistakes; the official description above is the record.