dbcve.org
Nx OsOperating system · Cisco

CVE-2018-0303

HIGH · 8.8 CVSS v3.0 Published 2018-06-21
Fix available
A fix is available. Upgrade to 1.1.4.179 / 2.0.1.153 or later.
See remediation →
93/100
Remediation priority · Urgent
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 Discovery Protocol component of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to execute arbitrary code as root or cause a denial of service (DoS) condition on the affected device. The vulnerability exists because of insufficiently validated Cisco Discovery Protocol packet headers. 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 cause a buffer overflow that could allow the attacker to execute arbitrary code as root or cause a DoS condition on the affected device. This vulnerability affects the following if configured to use Cisco Discovery Protocol: Firepower 4100 Series Next-Generation Firewalls, Firepower 9300 Security Appliance, MDS 9000 Series Multilayer Switches, Nexus 1000V Series Switches, Nexus 1100 Series Cloud Services Platforms, Nexus 2000 Series Fabric Extenders, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode, Nexus 9000 Series Switches in standalone NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, UCS 6100 Series Fabric Interconnects, UCS 6200 Series Fabric Interconnects, UCS 6300 Series Fabric Interconnects. Cisco Bug IDs: CSCvc22202, CSCvc22205, CSCvc22208, CSCvc88078, CSCvc88150, CSCvc88159, CSCvc88162, CSCvc88167.

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

A buffer overflow vulnerability in the Cisco Discovery Protocol (CDP) packet header validation allows an unauthenticated, adjacent attacker on the same Layer 2 network to send a crafted CDP packet and execute arbitrary code as root or cause a denial of service on affected Cisco FXOS and NX-OS devices.

MitigationDisable Cisco Discovery Protocol on affected devices if not required, or apply Cisco-provided patches for the specific product families (Firepower, MDS, Nexus, UCS) as identified in the corresponding bug IDs.

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:= 7.0\(0\)hsk\(0.357\)= 8.1\(0.2\)s0= 8.8\(0.1\)= 8.0\(1\)= 8.8\(3.5\)s0= 7.0\(3\)i4\(7\)= 7.0\(3\)i7\(1\)= 3.1\(3a\)a
Firepower Extensible Operating SystemOperating system
Affected:>= 1.1, < 1.1.4.179>= 2.0, < 2.0.1.153>= 2.1.1, < 2.1.1.86>= 2.2.1, < 2.2.1.70>= 2.2.2, < 2.2.2.17

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:3.0/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 checks

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

  1. Identify the NX-OS or FXOS version
    Run 'show version' or 'show inventory' on the device CLI to obtain the installed software version
    Affected if The displayed version matches one of the affected NX-OS versions listed (7.0(0)hsk(0.357), 8.1(0.2)s0, 8.8(0.1), 8.0(1), 8.8(3.5)s0, 7.0(3)i4(7), 7.0(3)i7(1), 3.1(3a)a) or falls within FXOS ranges (>=1.1 and <1.1.4.179, >=2.0 and <2.0.1.153, >=2.1.1 and <2.1.1.86, >=2.2.1 and <2.2.1.70, >=2.2.2 and
  2. Verify Cisco Discovery Protocol is enabled
    Run 'show cdp neighbor' or 'show run | include cdp' to check if CDP is actively running on the device
    Affected if CDP is enabled and operational (output shows CDP neighbors or 'cdp enable' in configuration)
  3. Confirm the device is directly accessible at Layer 2
    Determine if the device has physical or Layer 2 network interfaces exposed to untrusted adjacent attackers
    Affected if The device interfaces are reachable by unauthenticated adjacent attackers on the same Layer 2 network segment

The device is affected if it runs a vulnerable NX-OS or FXOS version from the affected ranges AND has Cisco Discovery Protocol enabled AND is accessible to adjacent attackers on the same Layer 2 network.

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 1.1.4.179 / 2.0.1.153 / 2.1.1.86 or later
Fixed in 1.1.4.1792.0.1.1532.1.1.86
Interim mitigation

Disable Cisco Discovery Protocol on affected devices if not required, or apply Cisco-provided patches for the specific product families (Firepower, MDS, Nexus, UCS) as identified in the corresponding bug IDs.

Fix this in Nx Os Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2018-0303 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2018-0303 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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