# CVE-2025-22040: ksmbd: fix session use-after-free in multichannel connection

> A race condition in the Linux kernel ksmbd module allows a use-after-free, potentially enabling local attackers to execute code or escalate privileges.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 16 Apr 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-22040, DEBIAN-CVE-2025-22040, GHSA-q9qg-fj9x-mqhg, ROOT-OS-UBUNTU-2204-CVE-2025-22040, ROOT-OS-UBUNTU-2404-CVE-2025-22040, UBUNTU-CVE-2025-22040

## What is CVE-2025-22040?

CVE-2025-22040 is a high-severity use after free vulnerability in Debian Debian Linux, published on 16 Apr 2025. 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: fix session use-after-free in multichannel connection

There is a race condition between session setup and
ksmbd_sessions_deregister. The session can be freed before the connection
is added to channel list of session.
This patch check reference count of session before freeing it.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2025-22040?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-22040?

Apply the vendor's patch.

## Is CVE-2025-22040 being exploited?

There is no known exploitation of CVE-2025-22040 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-22040 and fix it if it is affected.

What it is: CVE-2025-22040 is a high-severity use after free vulnerability in Debian Debian Linux, published on 16 Apr 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-22040 in the wild and no public exploit code.

Affected product: Debian Debian 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-2025-22040/ (Markdown: https://insights.sbomify.com/CVE-2025-22040/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-22040
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-22040
- OSV: https://osv.dev/vulnerability/CVE-2025-22040

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-22040/
Summaries are generated and may contain mistakes; the official description above is the record.