# CVE-2020-3165: Cisco NX-OS Software Border Gateway Protocol MD5 Authentication Bypass Vulnerability

> Remote attackers can bypass BGP MD5 authentication on Cisco NX-OS devices if specific VRF name length conditions are met, allowing unauthorized BGP session establishment.

- **Severity:** High 8.2 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Feb 2020
- **Updated:** 15 Nov 2024
- **Also known as:** GHSA-ggpf-8579-4r92

## What is CVE-2020-3165?

CVE-2020-3165 is a high-severity authentication bypass vulnerability in Cisco Nx-Os, published on 26 Feb 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the implementation of Border Gateway Protocol (BGP) Message Digest 5 (MD5) authentication in Cisco NX-OS Software could allow an unauthenticated, remote attacker to bypass MD5 authentication and establish a BGP connection with the device. The vulnerability occurs because the BGP MD5 authentication is bypassed if the peer does not have MD5 authentication configured, the NX-OS device does have BGP MD5 authentication configured, and the NX-OS BGP virtual routing and forwarding (VRF) name is configured to be greater than 19 characters. An attacker could exploit this vulnerability by attempting to establish a BGP session with the NX-OS peer. A successful exploit could allow the attacker to establish a BGP session with the NX-OS device without MD5 authentication. The Cisco implementation of the BGP protocol accepts incoming BGP traffic only from explicitly configured peers. To exploit this vulnerability, an attacker must send the malicious packets over a TCP connection that appears to come from a trusted BGP peer. To do so, the attacker must obtain information about the BGP peers in the affected system’s trusted network.

Weakness: CWE-798 (Use of Hard-coded Credentials)

## Which versions are affected by CVE-2020-3165?

It affects 1 product.


Products: Cisco Nx-Os.

## How do I fix CVE-2020-3165?

No fix has been published for CVE-2020-3165 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-3165 being exploited?

There is no known exploitation of CVE-2020-3165 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-2020-3165 and fix it if it is affected.

What it is: CVE-2020-3165 is a high-severity authentication bypass vulnerability in Cisco Nx-Os, published on 26 Feb 2020. 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-2020-3165 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-2020-3165/ (Markdown: https://insights.sbomify.com/CVE-2020-3165/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-3165
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-3165
- OSV: https://osv.dev/vulnerability/CVE-2020-3165

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-3165/
Summaries are generated and may contain mistakes; the official description above is the record.