# CVE-2020-3423: Cisco IOS XE Software Arbitrary Code Execution Vulnerability

> An authenticated local attacker can execute arbitrary code with root privileges on Cisco IOS XE devices by submitting a malicious Lua script that triggers a buffer overflow.

- **Severity:** Medium 5.1 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Sep 2020
- **Updated:** 13 Nov 2024
- **Also known as:** GHSA-g8rg-fgr5-jxrm

## What is CVE-2020-3423?

CVE-2020-3423 is a medium-severity memory corruption vulnerability in Cisco Ios Xe, published on 24 Sep 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 implementation of the Lua interpreter that is integrated in Cisco IOS XE Software could allow an authenticated, local attacker to execute arbitrary code with root privileges on the underlying Linux operating system (OS) of an affected device. The vulnerability is due to insufficient restrictions on Lua function calls within the context of user-supplied Lua scripts. An attacker with valid administrative credentials could exploit this vulnerability by submitting a malicious Lua script. When this file is processed, an exploitable buffer overflow condition could occur. A successful exploit could allow the attacker to execute arbitrary code with root privileges on the underlying Linux OS of the affected device.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2020-3423?

It affects 1 product.


Products: Cisco Ios Xe.

## How do I fix CVE-2020-3423?

No fix has been published for CVE-2020-3423 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-3423 being exploited?

There is no known exploitation of CVE-2020-3423 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Ios Xe

- [CVE-2023-20198](https://insights.sbomify.com/CVE-2023-20198/): Cisco IOS XE Web UI Privilege Escalation (critical 10.0, exploited in the wild)
- [CVE-2018-0151](https://insights.sbomify.com/CVE-2018-0151/): Cisco IOS Software and Cisco IOS XE Software Quality of Service Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2023-20273](https://insights.sbomify.com/CVE-2023-20273/): Cisco IOS XE Web UI Command Injection (high 7.2, exploited in the wild)
- [CVE-2025-20188](https://insights.sbomify.com/CVE-2025-20188/): Hardcoded credentials in Cisco IOS XE Software (critical 10.0)
- [CVE-2021-34770](https://insights.sbomify.com/CVE-2021-34770/): Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Remote Code Execution Vulnerability (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-3423 and fix it if it is affected.

What it is: CVE-2020-3423 is a medium-severity memory corruption vulnerability in Cisco Ios Xe, published on 24 Sep 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-2020-3423 in the wild and no public exploit code.

Affected product: Cisco Ios Xe. 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-2020-3423/ (Markdown: https://insights.sbomify.com/CVE-2020-3423/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-3423
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-3423
- OSV: https://osv.dev/vulnerability/CVE-2020-3423

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-3423/
Summaries are generated and may contain mistakes; the official description above is the record.