CVE-2019-1731: Cisco NX-OS Software SSH Key Information Disclosure Vulnerability

Severity: medium (CVSS 4.4 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-200

Description

A vulnerability in the SSH CLI key management functionality of Cisco NX-OS Software could allow an authenticated, local attacker to expose a user's private SSH key to all authenticated users on the targeted device. The attacker must authenticate with valid administrator device credentials. The vulnerability is due to incomplete error handling if a specific error type occurs during the SSH key export. An attacker could exploit this vulnerability by authenticating to the device and entering a crafted command at the CLI. A successful exploit could allow the attacker to expose a user's private SSH key. In addition, a similar type of error in the SSH key import could cause the passphrase-protected private SSH key to be imported unintentionally.

Affected products

Cisco NX-OS: before 7.0\(3\)i4\(9\); from 7.0\(3\)i7 before 7.0\(3\)i7\(4\); before 6.0\(2\)a8\(10\); from 7.0\(3\)i4 before 7.0\(3\)i7\(4\); before 7.3\(4\)n1\(1\); from 7.0\(3\) before 7.0\(3\)f3\(5\) — fixed in 6.0\(2\)a8\(10\), 7.0\(3\)f3\(5\), 7.0\(3\)i4\(9\), 7.0\(3\)i7\(4\), 7.3\(4\)n1\(1\)

How to fix

Upgrade to a fixed version: Cisco NX-OS 6.0\(2\)a8\(10\), 7.0\(3\)f3\(5\), 7.0\(3\)i4\(9\), 7.0\(3\)i7\(4\). Check the vendor advisory for mitigations.

References

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