# CVE-2026-90166: smb/server: fix null-ptr-deref in ksmbd_ipc_tree_connect_request()

> A null pointer dereference in the Linux kernel's ksmbd SMB server allows a low-privileged user to cause a denial of service.

- **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-102218, BELL-CVE-2026-90166, DEBIAN-CVE-2026-90166, GHSA-72gq-5j57-9667, UBUNTU-CVE-2026-90166

## What is CVE-2026-90166?

CVE-2026-90166 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:

smb/server: fix null-ptr-deref in ksmbd_ipc_tree_connect_request()

See the procedure below:

  ksmbd_tree_conn_connect
    ksmbd_share_config_get
      share->name = kstrdup() // fail
      if (!test_share_config_flag(share, KSMBD_SHARE_FLAG_PIPE)) // false
      // do not check `share->name`
    ksmbd_ipc_tree_connect_request
      strlen(share->name) // null-ptr-deref

## Which versions are affected by CVE-2026-90166?


## How do I fix CVE-2026-90166?

Apply the vendor's patch.

## Is CVE-2026-90166 being exploited?

There is no known exploitation of CVE-2026-90166 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90166 and fix it if it is affected.

What it is: CVE-2026-90166 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-2026-90166 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-2026-90166/ (Markdown: https://insights.sbomify.com/CVE-2026-90166/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90166
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90166
- OSV: https://osv.dev/vulnerability/CVE-2026-90166

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90166/
Summaries are generated and may contain mistakes; the official description above is the record.