# CVE-2021-47814: NBMonitor 1.6.8 - Denial of Service (PoC)

> Attackers can crash NBMonitor by pasting a long string into the registration field, causing denial of service.

- **Severity:** Medium 6.7 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 15 Jan 2026
- **Updated:** 5 Mar 2026
- **Also known as:** GHSA-c6rm-x44q-j5rw

## What is CVE-2021-47814?

CVE-2021-47814 is a medium-severity memory corruption vulnerability in Nsauditor NBMonitor, published on 15 Jan 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

NBMonitor 1.6.8 contains a denial of service vulnerability that allows attackers to crash the application by overflowing the registration code input field. Attackers can paste a 256-character buffer into the registration key field to trigger an application crash and potential system instability.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2021-47814?

It affects 1 product.


Products: Nsasoft Nbmonitor.

## How do I fix CVE-2021-47814?

No fix has been published for CVE-2021-47814 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-47814 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-47814 exists.

## Other vulnerabilities in Nsauditor NBMonitor

- [CVE-2020-37199](https://insights.sbomify.com/CVE-2020-37199/): NBMonitor 1.6.6.0 - 'Key' Denial of Service (medium 4.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-47814 and fix it if it is affected.

What it is: CVE-2021-47814 is a medium-severity memory corruption vulnerability in Nsauditor NBMonitor, published on 15 Jan 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-47814 exists.

Affected product: Nsauditor NBMonitor. 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-2021-47814/ (Markdown: https://insights.sbomify.com/CVE-2021-47814/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47814
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47814
- OSV: https://osv.dev/vulnerability/CVE-2021-47814

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47814/
Summaries are generated and may contain mistakes; the official description above is the record.