# CVE-2020-3503: Cisco IOS XE Software Guest Shell Unauthorized File System Access Vulnerability

> An authenticated local attacker can access or modify restricted system files via the guest shell due to insufficient permissions.

- **Severity:** Medium 6.0 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/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-328f-6h62-x2vm

## What is CVE-2020-3503?

CVE-2020-3503 is a medium-severity missing authorization 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 file system permissions of Cisco IOS XE Software could allow an authenticated, local attacker to obtain read and write access to critical configuration or system files. The vulnerability is due to insufficient file system permissions on an affected device. An attacker could exploit this vulnerability by connecting to an affected device's guest shell, and accessing or modifying restricted files. A successful exploit could allow the attacker to view or modify restricted information or configurations that are normally not accessible to system administrators.

Weakness: CWE-732 (Incorrect Permission Assignment for Critical Resource), CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2020-3503?

It affects 1 product.


Products: Cisco Ios Xe.

## How do I fix CVE-2020-3503?

No fix has been published for CVE-2020-3503 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-3503 being exploited?

There is no known exploitation of CVE-2020-3503 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-2020-3503 and fix it if it is affected.

What it is: CVE-2020-3503 is a medium-severity missing authorization 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-2020-3503 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-2020-3503/ (Markdown: https://insights.sbomify.com/CVE-2020-3503/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-3503
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-3503
- OSV: https://osv.dev/vulnerability/CVE-2020-3503

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-3503/
Summaries are generated and may contain mistakes; the official description above is the record.