CVE-2019-1809: Cisco NX-OS Software Patch Signature Verification Bypass Vulnerability

Severity: medium (CVSS 6.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% 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-347

Description

A vulnerability in the Image Signature Verification feature of Cisco NX-OS Software could allow an authenticated, local attacker with administrator-level credentials to install a malicious software patch on an affected device. The vulnerability is due to improper verification of digital signatures for patch images. An attacker could exploit this vulnerability by crafting an unsigned software patch to bypass signature checks and loading it on an affected device. A successful exploit could allow the attacker to boot a malicious software patch image.

Affected products

Cisco NX-OS: from 7.3 before 8.1\(1a\); from 8.2 before 8.3\(1\); from 7.2 before 7.3\(3\)d1\(1\); from 8.0 before 8.2\(3\); from 3.1 before 3.2\(3k\) — fixed in 3.2\(3k\), 7.3\(3\)d1\(1\), 8.1\(1a\), 8.2\(3\), 8.3\(1\)

How to fix

Upgrade to a fixed version: Cisco NX-OS 3.2\(3k\), 7.3\(3\)d1\(1\), 8.1\(1a\), 8.2\(3\). Check the vendor advisory for mitigations.

References

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