# CVE-2026-68381: ksmbd: pin conn during async oplock break notification

> A race condition in the Linux kernel ksmbd module allows use-after-free during oplock break notifications, potentially leading to code execution or denial of service.

- **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:** 10 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-68381, DEBIAN-CVE-2026-68381, GHSA-gq9g-pv9h-2q5v, UBUNTU-CVE-2026-68381

## What is CVE-2026-68381?

CVE-2026-68381 is a critical use after free vulnerability in Linux, published on 10 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:

ksmbd: pin conn during async oplock break notification

smb2_oplock_break_noti() and smb2_lease_break_noti() store a ksmbd_conn
pointer in an async ksmbd_work and then queue that work on ksmbd-io.  The
work only increments conn->r_count, which prevents teardown from passing
the pending-request wait after the increment, but it does not pin the
struct ksmbd_conn object.

If connection teardown races with an oplock break notification, the last
conn reference can be dropped before the queued worker finishes.  The
worker then uses the freed conn in ksmbd_conn_write() and
ksmbd_conn_r_count_dec().

Take a real conn reference when publishing the conn pointer to the async
work item, and drop it after the notification work has decremented
r_count.  Apply the same lifetime rule to lease break notification, which
uses the same work->conn pattern.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-68381?


## How do I fix CVE-2026-68381?

Apply the vendor's patch.

## Is CVE-2026-68381 being exploited?

There is no known exploitation of CVE-2026-68381 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68381 and fix it if it is affected.

What it is: CVE-2026-68381 is a critical use after free vulnerability in Linux, published on 10 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-2026-68381 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-2026-68381/ (Markdown: https://insights.sbomify.com/CVE-2026-68381/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68381
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68381
- OSV: https://osv.dev/vulnerability/CVE-2026-68381

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68381/
Summaries are generated and may contain mistakes; the official description above is the record.