# CVE-2025-22037: ksmbd: fix null pointer dereference in alloc_preauth_hash()

> A remote attacker can cause a denial of service in the Linux kernel's ksmbd server by sending malformed SMB2 requests that trigger a null pointer dereference.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:** 16 Apr 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-22037, DEBIAN-CVE-2025-22037, GHSA-gvg4-xh6r-ggrp, ROOT-OS-DEBIAN-12-CVE-2025-22037, ROOT-OS-UBUNTU-2204-CVE-2025-22037, ROOT-OS-UBUNTU-2404-CVE-2025-22037, UBUNTU-CVE-2025-22037

## What is CVE-2025-22037?

CVE-2025-22037 is a high-severity vulnerability in Linux kernel, published on 16 Apr 2025. 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: fix null pointer dereference in alloc_preauth_hash()

The Client send malformed smb2 negotiate request. ksmbd return error
response. Subsequently, the client can send smb2 session setup even
thought conn->preauth_info is not allocated.
This patch add KSMBD_SESS_NEED_SETUP status of connection to ignore
session setup request if smb2 negotiate phase is not complete.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2025-22037?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-22037?

Apply the vendor's patch.

## Is CVE-2025-22037 being exploited?

There is no known exploitation of CVE-2025-22037 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-22037 and fix it if it is affected.

What it is: CVE-2025-22037 is a high-severity vulnerability in Linux kernel, published on 16 Apr 2025. 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-2025-22037 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2025-22037/ (Markdown: https://insights.sbomify.com/CVE-2025-22037/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-22037
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-22037
- OSV: https://osv.dev/vulnerability/CVE-2025-22037

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-22037/
Summaries are generated and may contain mistakes; the official description above is the record.