# CVE-2026-89693: nfsd: check nfsd4_acl_to_attr() return value in nfsd4_create()

> An attacker can bypass ACL restrictions during file creation in the Linux kernel NFS server by exploiting unchecked return values.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-100163, BELL-CVE-2026-89693, DEBIAN-CVE-2026-89693, GHSA-hqc5-5f52-xmgw, UBUNTU-CVE-2026-89693

## What is CVE-2026-89693?

CVE-2026-89693 is a missing authorization vulnerability in Linux, published on 11 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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

nfsd: check nfsd4_acl_to_attr() return value in nfsd4_create()

nfsd4_create() stores the return value of nfsd4_acl_to_attr() in
status, but the switch(create->cr_type) block unconditionally
overwrites it in every branch. ACL translation errors are silently
discarded, and the CREATE proceeds without the requested ACL.

Add an early exit check after nfsd4_acl_to_attr(), matching the
pattern already used in nfsd4_setattr().

[ cel: prefer NFS4ERR_BADTYPE over NFS4ERR_ATTRNOTSUPP ]

## Which versions are affected by CVE-2026-89693?


## How do I fix CVE-2026-89693?

Apply the vendor's patch.

## Is CVE-2026-89693 being exploited?

There is no known exploitation of CVE-2026-89693 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89693 and fix it if it is affected.

What it is: CVE-2026-89693 is a missing authorization vulnerability in Linux, published on 11 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-89693 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-2026-89693/ (Markdown: https://insights.sbomify.com/CVE-2026-89693/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89693
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89693
- OSV: https://osv.dev/vulnerability/CVE-2026-89693

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89693/
Summaries are generated and may contain mistakes; the official description above is the record.