# CVE-2022-20623: Cisco Nexus 9000 Series Switches Bidirectional Forwarding Detection Denial of Service Vulnerability

> Remote attackers can cause denial of service on Cisco Nexus switches by triggering BFD session flaps via crafted traffic.

- **Severity:** High 8.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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:** 23 Feb 2022
- **Updated:** 6 Nov 2024
- **Also known as:** GHSA-p4xm-j739-93q3

## What is CVE-2022-20623?

CVE-2022-20623 is a high-severity denial of service vulnerability in Cisco Nx-Os, published on 23 Feb 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the rate limiter for Bidirectional Forwarding Detection (BFD) traffic of Cisco NX-OS Software for Cisco Nexus 9000 Series Switches could allow an unauthenticated, remote attacker to cause BFD traffic to be dropped on an affected device. This vulnerability is due to a logic error in the BFD rate limiter functionality. An attacker could exploit this vulnerability by sending a crafted stream of traffic through the device. A successful exploit could allow the attacker to cause BFD traffic to be dropped, resulting in BFD session flaps. BFD session flaps can cause route instability and dropped traffic, resulting in a denial of service (DoS) condition. This vulnerability applies to both IPv4 and IPv6 traffic.

Weakness: CWE-399

## Which versions are affected by CVE-2022-20623?

It affects 1 product.


Products: Cisco Nx-Os.

## How do I fix CVE-2022-20623?

No fix has been published for CVE-2022-20623 yet. Limit exposure of the affected software until one is available.

## Is CVE-2022-20623 being exploited?

There is no known exploitation of CVE-2022-20623 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-2022-20623 and fix it if it is affected.

What it is: CVE-2022-20623 is a high-severity denial of service vulnerability in Cisco Nx-Os, published on 23 Feb 2022. 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-2022-20623 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-2022-20623/ (Markdown: https://insights.sbomify.com/CVE-2022-20623/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-20623
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-20623
- OSV: https://osv.dev/vulnerability/CVE-2022-20623

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-20623/
Summaries are generated and may contain mistakes; the official description above is the record.