# CVE-2026-98172: smb: client: fix smbd_connection leak on cifs_get_tcp_session() error

> A memory leak in the Linux kernel SMB client allows remote attackers to cause denial of service by triggering connection errors.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-106104, BELL-CVE-2026-98172, DEBIAN-CVE-2026-98172, GHSA-h5hv-w97x-4565, UBUNTU-CVE-2026-98172

## What is CVE-2026-98172?

CVE-2026-98172 is a denial of service vulnerability in Linux, published on 6 Oct 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:

smb: client: fix smbd_connection leak on cifs_get_tcp_session() error

When an RDMA connection is successfully established via
smbd_get_connection() but cifs_get_tcp_session() later fails (e.g.
kthread_create() returns an error), the error path frees tcp_ses
without first destroying the smbd_connection.

Fix this by calling smbd_destroy() in the out_err cleanup path before
kfree(tcp_ses).  smbd_destroy() safely handles the case where
smbd_conn is NULL, so it can be called unconditionally.

## Which versions are affected by CVE-2026-98172?


## How do I fix CVE-2026-98172?

Apply the vendor's patch.

## Is CVE-2026-98172 being exploited?

There is no known exploitation of CVE-2026-98172 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98172 and fix it if it is affected.

What it is: CVE-2026-98172 is a denial of service vulnerability in Linux, published on 6 Oct 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-2026-98172 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-2026-98172/ (Markdown: https://insights.sbomify.com/CVE-2026-98172/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98172
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98172
- OSV: https://osv.dev/vulnerability/CVE-2026-98172

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98172/
Summaries are generated and may contain mistakes; the official description above is the record.