# CVE-2021-42973: Integer overflow in n/a

> Local attackers can execute arbitrary kernel-mode code or crash the system via a crafted I/O Request Packet in NoMachine Server.

- **Severity:** High 8.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Dec 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-mrjh-hc9f-vfff

## What is CVE-2021-42973?

CVE-2021-42973 is a high-severity vulnerability in n/a, published on 7 Dec 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

NoMachine Server is affected by Integer Overflow. IOCTL Handler 0x22001B in the NoMachine Server above 4.0.346 and below 7.7.4 allow local attackers to execute arbitrary code in kernel mode or cause a denial of service (memory corruption and OS crash) via specially crafted I/O Request Packet.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2021-42973?

It affects 1 product.


Products: Nomachine Server.

## How do I fix CVE-2021-42973?

No fix has been published for CVE-2021-42973 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-42973 being exploited?

There is no known exploitation of CVE-2021-42973 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-42972](https://insights.sbomify.com/CVE-2021-42972/): Memory corruption in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-42973 and fix it if it is affected.

What it is: CVE-2021-42973 is a high-severity vulnerability in n/a, published on 7 Dec 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-42973 in the wild and no public exploit code.

Affected product: n/a. 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-2021-42973/ (Markdown: https://insights.sbomify.com/CVE-2021-42973/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-42973
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-42973
- OSV: https://osv.dev/vulnerability/CVE-2021-42973

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-42973/
Summaries are generated and may contain mistakes; the official description above is the record.