# CVE-2026-90164: smb/server: abort initialization when proc setup fails

> A null pointer dereference in the Linux kernel SMB server can cause a denial of service when proc setup fails during initialization.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-90164, GHSA-6gqw-gw67-f4rg, UBUNTU-CVE-2026-90164

## What is CVE-2026-90164?

CVE-2026-90164 is a vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

smb/server: abort initialization when proc setup fails

ksmbd_server_init() calls ksmbd_proc_init() before creating the
remaining proc entries and server subsystems. ksmbd_proc_init() tears
down partial state on a procfs or percpu_counter allocation failure,
but returns void, so ksmbd_server_init() continues as if the counters
were usable.

Once userspace starts the server, server_ctrl_handle_init() calls
ksmbd_proc_reset(), which reaches percpu_counter_set() with a NULL
per-CPU counters pointer on SMP systems. The later ksmbd_proc_create()
calls also receive a NULL parent and may create entries in the /proc
root; ksmbd_proc_cleanup() cannot remove those entries because
ksmbd_proc_fs is NULL.

## Which versions are affected by CVE-2026-90164?


## How do I fix CVE-2026-90164?

Apply the vendor's patch.

## Is CVE-2026-90164 being exploited?

There is no known exploitation of CVE-2026-90164 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90164 and fix it if it is affected.

What it is: CVE-2026-90164 is a vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-90164 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-2026-90164/ (Markdown: https://insights.sbomify.com/CVE-2026-90164/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90164
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90164
- OSV: https://osv.dev/vulnerability/CVE-2026-90164

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90164/
Summaries are generated and may contain mistakes; the official description above is the record.