# CVE-2018-0833: Null dereference in Server Message Block

> A null dereference in the Windows SMB client allows attackers to cause a denial of service via specially crafted requests.

- **Severity:** Medium 5.3 (`CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/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:** No
- **Published:** 15 Feb 2018
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-m84f-8362-3v3c

## What is CVE-2018-0833?

CVE-2018-0833 is a medium-severity vulnerability in Microsoft Windows 8.1, published on 15 Feb 2018. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

The Microsoft Server Message Block 2.0 and 3.0 (SMBv2/SMBv3) client in Windows 8.1 and RT 8.1 and Windows Server 2012 R2 allows a denial of service vulnerability due to how specially crafted requests are handled, aka "SMBv2/SMBv3 Null Dereference Denial of Service Vulnerability".

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2018-0833?

It affects 3 products.


Products: Microsoft Windows 8.1, Microsoft Windows Rt 8.1, Microsoft Windows Server 2012.

## How do I fix CVE-2018-0833?

No fix has been published for CVE-2018-0833 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-0833 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-0833 exists.

Public exploit code:

- Microsoft Windows 8.1/2012 R2 - SMBv3 Null Pointer Dereference Denial of Service (exploitdb)

## Other vulnerabilities in Microsoft Windows 8.1

- [CVE-2017-0022](https://insights.sbomify.com/CVE-2017-0022/): Microsoft XML Core Services Information Disclosure (medium 6.5, exploited in the wild)
- [CVE-2016-3300](https://insights.sbomify.com/CVE-2016-3300/): Privilege escalation in n/a (high 7.8)
- [CVE-2016-0044](https://insights.sbomify.com/CVE-2016-0044/): Denial of service in n/a (high 7.5)
- [CVE-2015-2361](https://insights.sbomify.com/CVE-2015-2361/): Memory corruption in n/a (high 7.2)
- [CVE-2015-0058](https://insights.sbomify.com/CVE-2015-0058/): Double free vulnerability in win32k.sys in the kernel-mode drivers in Microsoft Windows 8.1, Windows Server 2012 R2, and Windows RT 8.1 allo (high 7.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-0833 and fix it if it is affected.

What it is: CVE-2018-0833 is a medium-severity vulnerability in Microsoft Windows 8.1, published on 15 Feb 2018. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-0833 exists.

Affected product: Microsoft Windows 8.1. 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-2018-0833/ (Markdown: https://insights.sbomify.com/CVE-2018-0833/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-0833
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-0833
- OSV: https://osv.dev/vulnerability/CVE-2018-0833

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-0833/
Summaries are generated and may contain mistakes; the official description above is the record.