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Nx OsOperating system · Cisco

CVE-2019-1728

MEDIUM · 6.7 CVSS v3.0 Published 2019-05-15
Fix available
A fix is available. Upgrade to 2.4.1.101 / 4.0 or later.
See remediation →
69/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability in the Secure Configuration Validation functionality of Cisco FXOS Software and Cisco NX-OS Software could allow an authenticated, local attacker to run arbitrary commands at system boot time with the privileges of root. The vulnerability is due to a lack of proper validation of system files when the persistent configuration information is read from the file system. An attacker could exploit this vulnerability by authenticating to the device and overwriting the persistent configuration storage with malicious executable files. An exploit could allow the attacker to run arbitrary commands at system startup and those commands will run as the root user. The attacker must have valid administrative credentials for the device.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Local privilege escalation vulnerability in Cisco FXOS and NX-OS Secure Configuration Validation where an authenticated administrator can overwrite persistent configuration storage files with malicious executables, causing arbitrary commands to execute as root at system boot.

MitigationApply Cisco patches when available; limit administrative access to trusted personnel; implement file integrity monitoring on configuration storage; ensure strong authentication controls for administrative accounts.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Nx OsOperating system
Affected:>= 8.1, < 8.1\(1b\)>= 8.2, < 8.3\(1\)>= 7.0\(3\)i7, < 7.0\(3\)i7\(3\)>= 6.0\(2\)a8, < 6.0\(2\)a8\(11\)>= 7.0\(3\), < 7.0\(3\)i7\(3\)>= 7.3, < 7.3\(4\)n1\(1\)>= 6.2, < 6.2\(22\)>= 7.2, < 7.3\(3\)d1\(1\)>= 8.0, < 8.3\(1\)>= 4.0, < 4.0\(1a\)>= 2.4, < 2.4.1.101

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify NX-OS version
    Run 'show version' or 'show version | include NX-OS' command on the device to obtain the installed software version.
    Affected if The installed version falls within any of these ranges: >=8.1 and <8.1(1b); >=8.2 and <8.3(1); >=7.0(3)i7 and <7.0(3)i7(3); >=6.0(2)a8 and <6.0(2)a8(11); >=7.0(3) and <7.0(3)i7(3); >=7.3 and <7.3(4)n1(1); >=6.2 and <6.2(22); >=7.2 and <7.3(3)d1(1); >=8.0 and <8.3(1); >=4.0 and <4.0(1a); >=2.4 and <2
  2. Verify Secure Configuration Validation feature status
    Run 'show running-config | include scv' or check the feature list with 'show feature' to see if Secure Configuration Validation is enabled.
    Affected if The Secure Configuration Validation feature is enabled on the device.
  3. Inspect persistent configuration storage directory
    Use 'dir bootflash:' or 'dir slot0:' to list files in persistent storage locations. Check for unexpected executable files or scripts in configuration directories.
    Affected if Unexpected executable files or scripts exist in persistent configuration storage locations that were not placed there by the administrator.
  4. Review boot configuration files for integrity
    Examine startup configuration files and boot scripts with 'show startup-config' and check the contents of /isanboot or boot directories for any unauthorized modifications.
    Affected if Startup configuration files or boot scripts contain unauthorized modifications, suspicious commands, or unexpected file references.

A device is affected if it runs a vulnerable NX-OS version listed above AND has the Secure Configuration Validation feature enabled, allowing an authenticated administrator to inject malicious content into persistent configuration storage.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 2.4.1.101 / 4.0 / 6.0 or later
Fixed in 2.4.1.1014.06.0
Interim mitigation

Apply Cisco patches when available; limit administrative access to trusted personnel; implement file integrity monitoring on configuration storage; ensure strong authentication controls for administrative accounts.

Fix this in Nx Os Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,640
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Scan for this in your stack

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dbcve dependency scanner

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2019-1728 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data