# CVE-2026-90167: ksmbd: serialize oplock close with pending break ownership

> A race condition in the Linux kernel ksmbd module allows attackers to cause denial of service or potentially execute code via oplock break handling.

- **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:** 17 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-102911, BELL-CVE-2026-90167, DEBIAN-CVE-2026-90167, GHSA-923f-jcq6-gqvq, UBUNTU-CVE-2026-90167

## What is CVE-2026-90167?

CVE-2026-90167 is a vulnerability in Linux, published on 17 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:

ksmbd: serialize oplock close with pending break ownership

close may abort an in-flight oplock break while another breaker already
holds an opinfo reference. Releasing pending_break wakes that waiter, but
without serializing the close transition with bit acquisition it can become
a new break owner through the test_and_set_bit() fast path. It can then
overwrite OPLOCK_CLOSING with OPLOCK_ACK_WAIT and continue a break for
a dying opinfo.

Make OPLOCK_CLOSING terminal once the opinfo is removed from the inode
list. Serialize that transition, pending_break acquisition, and
OPLOCK_ACK_WAIT setup with an opinfo state lock. A breaker which loses
the race releases its ownership and returns -ENOENT. Explicitly wake
pending_break waiters during close so they can observe the terminal state.

Also prevent ACK and timeout paths from replacing OPLOCK_CLOSING with
OPLOCK_STATE_NONE.

## Which versions are affected by CVE-2026-90167?


## How do I fix CVE-2026-90167?

Apply the vendor's patch.

## Is CVE-2026-90167 being exploited?

There is no known exploitation of CVE-2026-90167 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90167 and fix it if it is affected.

What it is: CVE-2026-90167 is a vulnerability in Linux, published on 17 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-2026-90167 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-2026-90167/ (Markdown: https://insights.sbomify.com/CVE-2026-90167/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90167
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90167
- OSV: https://osv.dev/vulnerability/CVE-2026-90167

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90167/
Summaries are generated and may contain mistakes; the official description above is the record.