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

Severity: medium (CVSS 6.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2019-05-15 · updated 2026-06-17
Weakness: CWE-264

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.

Affected products

Cisco NX-OS: from 7.0\(3\)i4 before 7.0\(3\)i4\(9\); from 7.0\(3\)i7 before 7.0\(3\)i7\(4\); from 8.1 before 8.3\(1\); from 7.0\(3\) before 7.0\(3\)f3\(5\) — fixed in 7.0\(3\)f3\(5\), 7.0\(3\)i4\(9\), 7.0\(3\)i7\(4\), 8.3\(1\)

How to fix

Upgrade to a fixed version: Cisco NX-OS 7.0\(3\)f3\(5\), 7.0\(3\)i4\(9\), 7.0\(3\)i7\(4\), 8.3\(1\). Check the vendor advisory for mitigations.

References

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