dbcve.org
Nx OsOperating system · Cisco

CVE-2019-1962

HIGH · 7.5 CVSS v3.0 Published 2019-08-28
Fix available
A fix is available. Upgrade to 3.2 / 4.0 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges 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 Cisco Fabric Services component of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause process crashes, which can result in a denial of service (DoS) condition on an affected system. The vulnerability is due to insufficient validation of TCP packets when processed by the Cisco Fabric Services over IP (CFSoIP) feature. An attacker could exploit this vulnerability by sending a malicious Cisco Fabric Services TCP packet to an affected device. A successful exploit could allow the attacker to cause process crashes, resulting in a device reload and a DoS condition. Note: There are three distribution methods that can be configured for Cisco Fabric Services. This vulnerability affects only distribution method CFSoIP, which is disabled by default. See the Details section for more information.

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 · moderate confidence

A vulnerability in the Cisco Fabric Services over IP (CFSoIP) feature of Cisco NX-OS allows an unauthenticated remote attacker to send malicious TCP packets that cause process crashes, resulting in device reload and denial of service. The root cause is insufficient validation of Cisco Fabric Services TCP packets.

MitigationEnsure CFSoIP remains disabled (it is disabled by default). If CFSoIP is required, apply vendor patches and consider network segmentation/ACLs to restrict access to trusted sources only.

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:>= 5.2, < 6.2\(29\)>= 7.3, < 8.1>= 7.0\(3\)f, < 9.2< 7.1\(5\)n1\(1b\)>= 7.3, < 7.3\(5\)n1\(1\)< 6.2\(22\)>= 7.2, < 7.3\(4\)d1\(1\)< 7.0\(3\)i4\(9\)>= 7.0\(3\)i7, < 7.0\(3\)i7\(6\)< 6.0\(2\)a8\(11\)< 3.2\(3i\)>= 4.0, < 4.0\(2d\)

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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
    Execute 'show version' on the device CLI to display the installed NX-OS version
    Affected if The displayed version falls within the affected ranges: >= 5.2, < 6.2(29); >= 7.3, < 8.1; >= 7.0(3)f, < 9.2; < 7.1(5)n1(1b); >= 7.3, < 7.3(5)n1(1); < 6.2(22); >= 7.2, < 7.3(4)d1(1); < 7.0(3)i4(9); >= 7.0(3)i7, < 7.0(3)i7(6); < 6.0(2)a8(11); < 3.2(3i); >= 4.0, < 4.0(2d)
  2. Verify CFSoIP feature status
    Execute 'show feature | include cfs' or 'show running-config | include cfs' to check if Cisco Fabric Services is enabled
    Affected if The feature output shows 'cfs' or 'fabric services' as enabled (note: CFSoIP is disabled by default)
  3. Confirm CFSoIP is actively listening
    Execute 'show cfs status' or 'show ip interface' to check if CFSoIP TCP ports (4786 is the default CFS port) are in listening state
    Affected if CFSoIP is actively listening on network ports and the NX-OS version is within the affected ranges

You are affected if your device runs a vulnerable NX-OS version AND CFSoIP is currently enabled and listening (the vulnerability only triggers when CFSoIP is actively running, not when disabled).

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 3.2 / 4.0 / 6.0 or later
Fixed in 3.24.06.0
Interim mitigation

Ensure CFSoIP remains disabled (it is disabled by default). If CFSoIP is required, apply vendor patches and consider network segmentation/ACLs to restrict access to trusted sources only.

Fix this in Nx Os Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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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-2019-1962 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