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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 17 Mar 2022.
iOSOperating system · Cisco

CVE-2018-0167

HIGH · 8.8 CVSS v3.1 Published 2018-03-28
Fix available
A fix is available. Upgrade to 5.1.3 or later.
See remediation →
99/100
Remediation priority · Urgent
In the wild 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
Multiple Buffer Overflow vulnerabilities in the Link Layer Discovery Protocol (LLDP) subsystem of Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition or execute arbitrary code with elevated privileges on an affected device. Cisco Bug IDs: CSCuo17183, CSCvd73487.

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

Multiple buffer overflow vulnerabilities exist in Cisco's Link Layer Discovery Protocol (LLDP) implementation across IOS, IOS XE, and IOS XR software. An unauthenticated attacker on the adjacent network can send specially crafted LLDP packets to cause denial of service or execute arbitrary code with elevated privileges on affected devices.

MitigationApply Cisco security patches for CSCuo17183 and CSCvd73487. Until patches are applied, consider disabling LLDP on untrusted network segments to reduce the 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
iOSOperating system
Affected:= 5.2.0.base<= 15.6.3m1<= 15.2\(6\)e0a<= 15.2\(4a\)ea5
Ios XeOperating system
Affected:= 5.2.0.base<= 15.6.3m1<= 15.2\(6\)e0a<= 15.2\(4a\)ea5
Ios XrOperating system
Affected:>= 4.1, < 5.1.3

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. Identify the Cisco software product
    Run 'show version' to determine if the device runs iOS, iOS XE, or iOS XR
    Affected if Product is Cisco iOS, iOS XE, or iOS XR and version falls within affected ranges
  2. Check the iOS/iOS XE version number
    Run 'show version' and locate the version string (e.g., 15.2(4a)ea5, 15.6(3)m1, 15.2(6)e0a)
    Affected if Version equals 5.2.0.base, is less than or equal to 15.6.3m1, is less than or equal to 15.2(6)e0a, or is less than or equal to 15.2(4a)ea5
  3. Check the IOS XR version number
    Run 'show version' for IOS XR devices and locate the version string
    Affected if Version is greater than or equal to 4.1 and less than 5.1.3
  4. Verify if LLDP is enabled
    Run 'show lldp' or 'show lldp neighbors' to check LLDP status; run 'show run | include lldp' to check configuration
    Affected if LLDP is globally enabled or enabled on any interface (vulnerability only applies when LLDP is active)
  5. Check for LLDP-enabled interfaces
    Run 'show lldp interface' to list interfaces with LLDP transmit or receive enabled
    Affected if Any interface has LLDP transmit or receive capability enabled

Device is affected if it runs a vulnerable iOS/iOS XE/IOS XR version AND has LLDP globally enabled or enabled on at least one interface.

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.

dbcve · scoped
Upgrade available Upgrade to 5.1.3 or later
Fixed in 5.1.3
Interim mitigation

Apply Cisco security patches for CSCuo17183 and CSCvd73487. Until patches are applied, consider disabling LLDP on untrusted network segments to reduce the attack surface.

Recommended fix Moderate confidence

Cisco IOS XR fixed in 5.1.3 and later; Cisco IOS/IOS XE fixed in later 15.x releases per cisco-sa-20180502-lldp advisory

  1. 1. Identify the exact Cisco IOS, IOS XE, or IOS XR version running on the device using the 'show version' command
  2. 2. Determine the product platform and model to ensure compatibility with the fixed release
  3. 3. Review Cisco Security Advisory cisco-sa-20180502-lldp for the complete list of fixed releases for your specific platform
  4. 4. Download the appropriate fixed Cisco IOS/IOS XE/IOS XR software image from Cisco.com or your Cisco smart account
  5. 5. Plan a maintenance window as upgrade requires device reload
  6. 6. Backup current device configuration using 'copy running-config startup-config' or archive the configuration
  7. 7. Transfer the new software image to the device using TFTP, FTP, SCP, or USB
  8. 8. Set the boot system to point to the new image using 'boot system <image>' in global configuration mode
Caveat Upgrade may cause temporary service disruption as device reloads; ensure compatibility with existing network topology and review release notes for any behavioral changes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in iOS Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2018-0167 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