# CVE-2026-20212: Cisco Nexus 3000 and 9000 Series Switches Silicon One Hardware Abstraction Layer Remote Code Execution Vulnerability

> Unauthenticated remote attackers can execute arbitrary code with root privileges on Cisco Nexus switches via exposed TCP ports.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:** 2 Sep 2026
- **Updated:** 3 Sep 2026
- **Also known as:** GHSA-6g5h-4mv8-prv7

## What is CVE-2026-20212?

CVE-2026-20212 is a critical code injection vulnerability in Cisco NX-OS Software, published on 2 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the Silicon One integration for Cisco Nexus 9000 Series Switches could allow an unauthenticated, remote attacker to execute code with root privileges.

This vulnerability exists because TCP ports 43210 and 43211 are accessible in the default Layer 3 (L3) virtual routing and forwarding (VRF). A successful exploit could allow the attacker to connect to an affected device and send crafted input that could be executed as code with root privileges. The exploitation of this vulnerability could also cause the S1HAL process to crash, which could cause the device to reload.

Weakness: CWE-1327 (Binding to an Unrestricted IP Address)

## Which versions are affected by CVE-2026-20212?


## How do I fix CVE-2026-20212?

No fix has been published for CVE-2026-20212 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-20212 being exploited?

There is no known exploitation of CVE-2026-20212 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-20212 - Draft or TODO (github_poc): https://github.com/HORKimhab/CVE-2026-20212

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-20212 and fix it if it is affected.

What it is: CVE-2026-20212 is a critical code injection vulnerability in Cisco NX-OS Software, published on 2 Sep 2026. 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-2026-20212 in the wild and no public exploit code.

Affected product: Cisco NX-OS Software. 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-2026-20212/ (Markdown: https://insights.sbomify.com/CVE-2026-20212/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20212
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-20212
- OSV: https://osv.dev/vulnerability/CVE-2026-20212

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-20212/
Summaries are generated and may contain mistakes; the official description above is the record.