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Nx OsOperating system · Cisco

CVE-2016-1465

MEDIUM · 6.5 CVSS v3.0 Published 2016-07-28
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
70/100
Remediation priority · Elevated
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
Cisco Nexus 1000v Application Virtual Switch (AVS) devices before 5.2(1)SV3(1.5i) allow remote attackers to cause a denial of service (ESXi hypervisor crash and purple screen) via a crafted Cisco Discovery Protocol packet that triggers an out-of-bounds memory access, aka Bug ID CSCuw57985.

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

Cisco Nexus 1000v Application Virtual Switch (AVS) devices before version 5.2(1)SV3(1.5i) contain a denial of service vulnerability where processing a crafted Cisco Discovery Protocol (CDP) packet triggers an out-of-bounds memory access. This causes the underlying ESXi hypervisor to crash, resulting in a purple screen of death.

MitigationUpgrade Cisco Nexus 1000v AVS to version 5.2(1)SV3(1.5i) or later. As a compensating control, restrict physical switch ports or VLANs carrying CDP traffic to trusted sources to reduce attack surface.

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:= 4.0\(4\)sv1\(1\)= 4.0\(4\)sv1\(2\)= 4.0\(4\)sv1\(3\)= 4.0\(4\)sv1\(3a\)= 4.0\(4\)sv1\(3b\)= 4.0\(4\)sv1\(3c\)= 4.0\(4\)sv1\(3d\)= 4.2\(1\)sv1\(4\)= 4.2\(1\)sv1\(4a\)= 4.2\(1\)sv1\(4b\)= 4.2\(1\)sv1\(5.1\)= 4.2\(1\)sv1\(5.1a\)

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

CVSS:3.0/AV:A/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. Confirm Cisco Nexus 1000v AVS is deployed
    Identify the installed virtual switch type. On the ESXi host, run 'esxcli network switch list' or check vCenter for the virtual switch type. This vulnerability affects only the Application Virtual Switch (AVS) variant, not standard Nexus 1000v or other virtual switches.
    Affected if The virtual switch is NOT the Cisco Nexus 1000v AVS variant, then not affected by this specific CVE.
  2. Check AVS software version
    On the ESXi host console or via 'esxcli system module list', identify the loaded AVS module version. Alternatively, from Nexus 1000v CLI, run 'show version' to display the AVS software version.
    Affected if The installed version is one of: 4.0(4)sv1(1), 4.0(4)sv1(2), 4.0(4)sv1(3), 4.0(4)sv1(3a), 4.0(4)sv1(3b), 4.0(4)sv1(3c), 4.0(4)sv1(3d), 4.2(1)sv1(4), 4.2(1)sv1(4a), 4.2(1)sv1(4b), 4.2(1)sv1(5.1), or 4.2(1)sv1(5.1a). Versions prior to 5.2(1)SV3(1.5i) are affected.
  3. Verify CDP is enabled on the virtual switch
    From the Nexus 1000v AVS CLI, run 'show cdp neighbor' or 'show run | include cdp' to determine if Cisco Discovery Protocol is active on any interface or VLAN.
    Affected if CDP is enabled on any interface or VLAN - the vulnerability is triggered by processing CDP packets, so CDP must be active for exploitation.
  4. Confirm ESXi hypervisor version in use
    Run 'vmware -v' or check 'esxcli system version get' on the ESXi host where the AVS is running.
    Affected if The vulnerability causes ESXi hypervisor crashes leading to purple screen, but the AVS version determines vulnerability, not the hypervisor version alone.

Your environment is affected if you are running Cisco Nexus 1000v AVS with a version between 4.0(4)sv1(1) and 4.2(1)sv1(5.1a) and Cisco Discovery Protocol is enabled on the virtual switch.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Cisco Nexus 1000v AVS to version 5.2(1)SV3(1.5i) or later. As a compensating control, restrict physical switch ports or VLANs carrying CDP traffic to trusted sources to reduce attack surface.

Fix this in Nx Os Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,580
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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-2016-1465 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