Nx OsOperating system · Cisco
CVE-2020-3415
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 · uneditedA vulnerability in the Data Management Engine (DME) of Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to execute arbitrary code with administrative privileges or cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by sending a crafted Cisco Discovery Protocol packet to a Layer 2-adjacent affected device. A successful exploit could allow the attacker to execute arbitrary code with administrative privileges or cause the Cisco Discovery Protocol process to crash and restart multiple times, causing the affected device to reload and resulting in a DoS condition. Note: Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent). Exploitation of this vulnerability also requires jumbo frames to be enabled on the interface that receives the crafted Cisco Discovery Protocol packets on the affected 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 confidenceA vulnerability in Cisco NX-OS Data Management Engine (DME) allows an unauthenticated, Layer 2-adjacent attacker to execute arbitrary code with administrative privileges or cause a DoS by sending a crafted Cisco Discovery Protocol packet. Exploitation requires jumbo frames to be enabled on the receiving interface and the attacker must be on the same broadcast domain.
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
all versions>= 4.0, < 4.0\(4h\)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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:A/AC:L/PR:N/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 checksWork through these to decide whether this CVE applies to you.
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Check NX-OS versionRun 'show version' command and locate the NX-OS release string in the outputAffected if Version is 4.0 or later but earlier than 4.0(4h)
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Verify Cisco Discovery Protocol is enabledRun 'show cdp neighbor' or 'show cdp interface' to determine if CDP is currently active on any interfaceAffected if CDP is enabled on any interface (the vulnerability is exploited via crafted CDP packets)
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Confirm jumbo frames are enabledRun 'show interface <interface> | include MTU' for each active interface, or use 'show running-config | include mtu' to check global MTU settingsAffected if Jumbo frames (MTU > 1500) are enabled on any receiving interface - this is a required condition for exploitation
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Identify Layer 2 adjacent devicesReview 'show cdp neighbor' output to see what devices are on the same broadcast domainAffected if Any unknown or untrusted devices are visible as CDP neighbors on the same Layer 2 segment
A system is affected if it runs a vulnerable NX-OS version (4.0 through before 4.0(4h)), has CDP enabled, has jumbo frames configured on a receiving interface, and has untrusted devices Layer 2 adjacent.
Generated from the published advisory. Verify against your own configuration.
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 data4.0
Apply the Cisco-provided software patch/update for NX-OS. If patching is delayed, consider disabling Cisco Discovery Protocol on untrusted interfaces or disabling jumbo frames as a temporary workaround until the patch can be applied.
Fix this in Nx Os
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3415 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-3415 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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