dbcve.org
Nx OsOperating system · Cisco

CVE-2019-1901

HIGH · 8.8 CVSS v3.1 Published 2019-07-31
Fix available
A fix is available. Upgrade to 13.2 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 Link Layer Discovery Protocol (LLDP) subsystem of Cisco Nexus 9000 Series Application Centric Infrastructure (ACI) Mode Switch Software could allow an adjacent, unauthenticated attacker to cause a denial of service (DoS) condition or execute arbitrary code with root privileges. The vulnerability is due to improper input validation of certain type, length, value (TLV) fields of the LLDP frame header. An attacker could exploit this vulnerability by sending a crafted LLDP packet to the targeted device. A successful exploit may lead to a buffer overflow condition that could either cause a DoS condition or allow the attacker to execute arbitrary code with root privileges. Note: This vulnerability cannot be exploited by transit traffic through the device; the crafted packet must be targeted to a directly connected interface. This vulnerability affects Cisco Nexus 9000 Series Fabric Switches in ACI mode if they are running a Cisco Nexus 9000 Series ACI Mode Switch Software release prior to 13.2(7f) or any 14.x release.

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 the LLDP subsystem of Cisco Nexus 9000 Series ACI Mode switches due to improper input validation of TLV fields in crafted LLDP packets. An adjacent unauthenticated attacker with direct network access can send malicious LLDP packets to cause denial of service or execute arbitrary code with root privileges.

MitigationUpgrade Cisco Nexus 9000 Series ACI Mode Switch Software to release 13.2(7f) or later (or a fixed 14.x release), and limit LLDP exposure on untrusted network segments as a defense-in-depth measure.

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:< 13.2\(7f\)>= 14.0\(1h\), <= 14.1\(2g\)

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 checks

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

  1. Confirm the device is a Cisco Nexus 9000 Series ACI Mode switch
    Identify the hardware model using 'show version' or 'show inventory' command output. Look for 'Nexus 9000' in ACI mode.
    Affected if The device is not a Cisco Nexus 9000 Series ACI Mode switch, this CVE does not apply.
  2. Check the installed software version
    Execute 'show version' and locate the 'system: version' line. Compare the full version number against the affected ranges: any version < 13.2(7f) or >= 14.0(1h) through 14.1(2g) are vulnerable.
    Affected if The installed version falls within < 13.2(7f) or between 14.0(1h) and 14.1(2g) inclusive.
  3. Verify if LLDP is enabled
    Run 'show lldp' or 'show lldp neighbors' to check the LLDP configuration status. LLDP is enabled by default on these switches.
    Affected if LLDP is globally enabled or enabled on the exposed interfaces.
  4. Check network exposure of LLDP-capable interfaces
    Review 'show lldp neighbors' output to see which interfaces have LLDP adjacency, and evaluate whether these network segments are trusted or accessible to adjacent unauthenticated attackers.
    Affected if LLDP is enabled on interfaces facing untrusted or directly accessible network segments.

The device is affected if it is a Cisco Nexus 9000 Series ACI Mode switch running a vulnerable software version (less than 13.2(7f) or between 14.0(1h) and 14.1(2g)) with LLDP enabled on accessible interfaces.

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 13.2 or later
Fixed in 13.2
Interim mitigation

Upgrade Cisco Nexus 9000 Series ACI Mode Switch Software to release 13.2(7f) or later (or a fixed 14.x release), and limit LLDP exposure on untrusted network segments as a defense-in-depth measure.

Fix this in Nx Os Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,968.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2019-1901 — 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-2019-1901 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