# CVE-2018-0331: Denial of service in Cisco FXOS, NX-OS, and UCS Manager unknown

> An unauthenticated adjacent attacker can cause a denial of service on Cisco NX-OS devices by sending malformed Cisco Discovery Protocol messages.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:A/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Jun 2018
- **Updated:** 29 Nov 2024
- **Also known as:** GHSA-frp3-j6g7-xf43

## What is CVE-2018-0331?

CVE-2018-0331 is a medium-severity denial of service vulnerability in Cisco Firepower Extensible Operating System, published on 21 Jun 2018. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability in the Cisco Discovery Protocol (formerly known as CDP) subsystem of devices running, or based on, Cisco NX-OS Software contain a vulnerability that could allow an unauthenticated, adjacent attacker to create a denial of service (DoS) condition. The vulnerability is due to a failure to properly validate certain fields within a Cisco Discovery Protocol message prior to processing it. An attacker with the ability to submit a Cisco Discovery Protocol message designed to trigger the issue could cause a DoS condition on an affected device while the device restarts. This vulnerability affects Firepower 4100 Series Next-Generation Firewall, Firepower 9300 Security Appliance, MDS 9000 Series Multilayer Director Switches, Nexus 1000V Series Switches, Nexus 1100 Series Cloud Services Platforms, Nexus 2000 Series Switches, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 3600 Platform Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, UCS 6100 Series Fabric Interconnects, UCS 6200 Series Fabric Interconnects, UCS 6300 Series Fabric Interconnects. Cisco Bug IDs: CSCvc89242, CSCve40943, CSCve40953, CSCve40965, CSCve40970, CSCve40978, CSCve40992, CSCve41000, CSCve41007.

Weakness: CWE-20 (Improper Input Validation), CWE-399

## Which versions are affected by CVE-2018-0331?

It affects 3 products.


Products: Cisco Firepower Extensible Operating System, Cisco Fxos, Cisco Nx-Os.

## How do I fix CVE-2018-0331?

No fix has been published for CVE-2018-0331 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-0331 being exploited?

There is no known exploitation of CVE-2018-0331 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Firepower Extensible Operating System

- [CVE-2018-0310](https://insights.sbomify.com/CVE-2018-0310/): Information disclosure in Cisco FXOS and NX-OS unknown (critical 9.8)
- [CVE-2015-6435](https://insights.sbomify.com/CVE-2015-6435/): Command injection in n/a (critical 9.8)
- [CVE-2021-1368](https://insights.sbomify.com/CVE-2021-1368/): Memory corruption in Cisco NX-OS Software (high 8.8)
- [CVE-2020-3456](https://insights.sbomify.com/CVE-2020-3456/): Cisco FXOS Software Firepower Chassis Manager Cross-Site Request Forgery Vulnerability (high 8.8)
- [CVE-2020-3172](https://insights.sbomify.com/CVE-2020-3172/): Cisco FXOS and NX-OS Software Cisco Discovery Protocol Arbitrary Code Execution and Denial of Service Vulnerability (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-0331 and fix it if it is affected.

What it is: CVE-2018-0331 is a medium-severity denial of service vulnerability in Cisco Firepower Extensible Operating System, published on 21 Jun 2018. 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-2018-0331 in the wild and no public exploit code.

Affected product: Cisco Firepower Extensible Operating System. 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-2018-0331/ (Markdown: https://insights.sbomify.com/CVE-2018-0331/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-0331
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-0331
- OSV: https://osv.dev/vulnerability/CVE-2018-0331

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-0331/
Summaries are generated and may contain mistakes; the official description above is the record.