# CVE-2020-3174: Cisco NX-OS Software Anycast Gateway Invalid ARP Vulnerability

> An adjacent attacker can corrupt ARP tables via malicious GARP packets in Cisco NX-OS anycast gateway, causing traffic disruptions.

- **Severity:** Medium 4.7 (`CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Feb 2020
- **Updated:** 15 Nov 2024
- **Also known as:** GHSA-44pg-r8gr-j75x

## What is CVE-2020-3174?

CVE-2020-3174 is a medium-severity vulnerability in Cisco Nx-Os, published on 26 Feb 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability in the anycast gateway feature of Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a device to learn invalid Address Resolution Protocol (ARP) entries. The ARP entries are for nonlocal IP addresses for the subnet. The vulnerability is due to improper validation of a received gratuitous ARP (GARP) request. An attacker could exploit this vulnerability by sending a malicious GARP packet on the local subnet to cause the ARP table on the device to become corrupted. A successful exploit could allow the attacker to populate the ARP table with incorrect entries, which could lead to traffic disruptions.

Weakness: CWE-345 (Insufficient Verification of Data Authenticity)

## Which versions are affected by CVE-2020-3174?

It affects 1 product.


Products: Cisco Nx-Os.

## How do I fix CVE-2020-3174?

No fix has been published for CVE-2020-3174 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-3174 being exploited?

There is no known exploitation of CVE-2020-3174 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Nx-Os

- [CVE-2024-20399](https://insights.sbomify.com/CVE-2024-20399/): Cisco NX-OS Command Injection (medium 6.0, exploited in the wild)
- [CVE-2021-1361](https://insights.sbomify.com/CVE-2021-1361/): Cisco NX-OS Software Unauthenticated Arbitrary File Actions Vulnerability (critical 9.8)
- [CVE-2018-0301](https://insights.sbomify.com/CVE-2018-0301/): Memory corruption in Cisco NX-OS unknown (critical 9.8)
- [CVE-2016-1453](https://insights.sbomify.com/CVE-2016-1453/): Memory corruption in n/a (critical 9.8)
- [CVE-2016-1341](https://insights.sbomify.com/CVE-2016-1341/): Hardcoded credentials in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-3174 and fix it if it is affected.

What it is: CVE-2020-3174 is a medium-severity vulnerability in Cisco Nx-Os, published on 26 Feb 2020. 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-2020-3174 in the wild and no public exploit code.

Affected product: Cisco Nx-Os. 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-2020-3174/ (Markdown: https://insights.sbomify.com/CVE-2020-3174/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-3174
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-3174
- OSV: https://osv.dev/vulnerability/CVE-2020-3174

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-3174/
Summaries are generated and may contain mistakes; the official description above is the record.