# CVE-2021-23270: Denial of service in n/a

> An attacker can cause excessive network traffic and potential service disruption on Gargoyle OS devices by exploiting IPv6 routing loop conditions.

- **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:** No
- **Published:** 12 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-wqw9-vmhv-jg2w

## What is CVE-2021-23270?

CVE-2021-23270 is a high-severity denial of service vulnerability in n/a, published on 12 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In Gargoyle OS 1.12.0, when IPv6 is used, a routing loop can occur that generates excessive network traffic between an affected device and its upstream ISP's router. This occurs when a link prefix route points to a point-to-point link, a destination IPv6 address belongs to the prefix and is not a local IPv6 address, and a router advertisement is received with at least one global unique IPv6 prefix for which the on-link flag is set.

Weakness: CWE-834 (Excessive Iteration)

## Which versions are affected by CVE-2021-23270?

It affects 1 product.


Products: Gargoyle-Router Gargoyle.

## How do I fix CVE-2021-23270?

No fix has been published for CVE-2021-23270 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-23270 being exploited?

There is no known exploitation of CVE-2021-23270 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2015-10145](https://insights.sbomify.com/CVE-2015-10145/): Gargoyle 1.5.x Authenticated OS Command Execution via run_commands.sh (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-23270 and fix it if it is affected.

What it is: CVE-2021-23270 is a high-severity denial of service vulnerability in n/a, published on 12 Apr 2021. 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-2021-23270 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-2021-23270/ (Markdown: https://insights.sbomify.com/CVE-2021-23270/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-23270
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-23270
- OSV: https://osv.dev/vulnerability/CVE-2021-23270

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-23270/
Summaries are generated and may contain mistakes; the official description above is the record.