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Nx OsOperating system · Cisco

CVE-2019-1616

HIGH · 7.5 CVSS v3.0 Published 2019-03-11
Fix available
A fix is available. Upgrade to 6.2 / 7.0 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 a buffer overflow, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient validation of Cisco Fabric Services packets. An attacker could exploit this vulnerability by sending a crafted Cisco Fabric Services packet to an affected device. A successful exploit could allow the attacker to cause a buffer overflow, resulting in process crashes and a DoS condition on the device. MDS 9000 Series Multilayer Switches are affected running software versions prior to 6.2(25), 8.1(1b), 8.3(1). Nexus 3000 Series Switches are affected running software versions prior to 7.0(3)I4(9) and 7.0(3)I7(4). Nexus 3500 Platform Switches are affected running software versions prior to 6.0(2)A8(10) and 7.0(3)I7(4). Nexus 3600 Platform Switches are affected running software versions prior to 7.0(3)F3(5) Nexus 7000 and 7700 Series Switches are affected running software versions prior to 6.2(22) and 8.2(3). Nexus 9000 Series Switches in Standalone NX-OS Mode are affected running software versions prior to 7.0(3)I4(9) and 7.0(3)I7(4). Nexus 9500 R-Series Line Cards and Fabric Modules are affected running software versions prior to 7.0(3)F3(5). UCS 6200, 6300, and 6400 Fabric Interconnects are affected running software versions prior to 3.2(3j) and 4.0(2a).

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

Buffer overflow vulnerability in Cisco Fabric Services component of NX-OS Software allows unauthenticated remote attackers to send crafted packets that overflow a buffer, causing process crashes and denial of service. The root cause is insufficient validation of Cisco Fabric Services packet data before copying into fixed-length buffers.

MitigationApply vendor-supplied software updates to reach the fixed versions (MDS: 6.2(25)/8.1(1b)/8.3(1), Nexus 3000/9000: 7.0(3)I4(9)/7.0(3)I7(4), Nexus 7000/7700: 6.2(22)/8.2(3), etc.) as listed in the Cisco advisory.

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:>= 8.2, < 8.3\(1\)>= 7.0\(3\), < 7.0\(3\)i7\(4\)>= 7.0\(3\)i5, < 7.0\(3\)i7\(4\)>= 7.0\(3\)f3, < 7.0\(3\)f3\(3c\)>= 7.2, < 8.2\(3\)>= 7.0\(3\)f1, < 7.0\(3\)f3\(3c\)>= 7.3, < 8.1\(1b\)>= 5.2, < 6.2\(25\)>= 7.0\(3\)i4, < 7.0\(3\)i4\(9\)>= 6.2, < 6.2\(22\)< 6.2\(22\)< 7.0\(3\)i4\(9\)

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 and locate the 'NXOS' version line (typically shows as something like 7.0(3)I4(9) or 8.2(1))
    Affected if The installed version falls within any of these ranges: >=8.2 but <8.3(1); >=7.0(3) but <7.0(3)I7(4); >=7.0(3)I5 but <7.0(3)I7(4); >=7.0(3)F3 but <7.0(3)F3(3c); >=7.2 but <8.2(3); >=7.0(3)F1 but <7.0(3)F3(3c); >=7.3 but <8.1(1b); >=5.2 but <6.2(25); >=7.0(3)I4 but <7.0(3)I4(9); >=6.2 but <6.2(22); o
  2. Verify Cisco Fabric Services is enabled
    Run 'show cfs status' to check if Cisco Fabric Services is enabled on the device
    Affected if The CFS status shows the service as enabled (even if distributed merge is disabled, the process may still be listening)
  3. Check if CFS IPv4 or IPv6 is bound to an interface
    Run 'show cfs internal network' or 'show cfs ipv4 status' to see if Fabric Services has an active network binding
    Affected if CFS is bound to any IP interface (management or VLANs), indicating the service is reachable over the network
  4. Review process crash logs for CFS
    Run 'show process crashinfo | include cfs' or check 'show logging last 100 | include CFS' for recent crash events
    Affected if Any CFS-related process crashes are observed in the logs, especially unexpected restarts

The device is affected if it runs a vulnerable NX-OS version (from the ranges above) AND Cisco Fabric Services is enabled and network-reachable on the device.

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 6.2 / 7.0 / 8.1 or later
Fixed in 6.27.08.1
Interim mitigation

Apply vendor-supplied software updates to reach the fixed versions (MDS: 6.2(25)/8.1(1b)/8.3(1), Nexus 3000/9000: 7.0(3)I4(9)/7.0(3)I7(4), Nexus 7000/7700: 6.2(22)/8.2(3), etc.) as listed in the Cisco advisory.

Fix this in Nx Os Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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Scan for this in your stack

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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-2019-1616 in production — separate from our analysis above.

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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