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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-2018-0175

HIGH · 8.0 CVSS v3.1 Published 2018-03-28
Fix available
A fix is available. Upgrade to after 15.6.3m1 or later.
See remediation →
97/100
Remediation priority · Urgent
In the wild No privileges

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
Format String vulnerability 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: CSCvd73664.

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 format string vulnerability exists in the Link Layer Discovery Protocol (LLDP) implementation across Cisco IOS, IOS XE, and IOS XR software. An unauthenticated attacker on the same layer-2 network segment can send specially crafted LLDP packets that, due to improper input handling in the format string, can either crash the affected device (DoS) or potentially execute arbitrary code with elevated (root) privileges.

MitigationApply the vendor patch from Cisco when available. If immediate patching is not feasible, consider disabling LLDP on untrusted network segments or implementing network access control to restrict unauthorized adjacent attackers from reaching the LLDP service.

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:= 15.4\(3\)m4.1<= 15.2\(4a\)ea5<= 15.2\(6\)e0a<= 15.6.3m1
Ios XeOperating system
Affected:= 15.4\(3\)m4.1<= 15.2\(4a\)ea5<= 15.2\(6\)e0a<= 15.6.3m1
Ios XrOperating system
Affected:= 15.4\(3\)m4.1

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
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:R/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 device software version
    Run 'show version' on the device CLI and locate the version string (e.g., 15.4(3)M4.1, 15.2(4a)EA5, 15.2(6)E0a, 15.6(3)M1)
    Affected if Version exactly equals 15.4(3)M4.1 OR is 15.2(4a)EA5 or lower OR is 15.2(6)E0a or lower OR is 15.6(3)M1 or lower (for iOS/IOS Xe); version exactly equals 15.4(3)M4.1 for IOS XR
  2. Confirm device platform runs iOS, IOS Xe, or IOS XR
    Run 'show version' and check the platform type (IOS, IOS XE, or IOS XR) in the output
    Affected if Device runs Cisco iOS, IOS XE, or IOS XR matching the version criteria above
  3. Check if LLDP is enabled
    Run 'show lldp' or 'show lldp neighbors' and verify LLDP is running/enabled
    Affected if LLDP protocol is enabled and running on the device (vulnerability requires LLDP to be active)

Device is affected if it runs iOS, IOS XE, or IOS XR matching the specified version ranges AND has LLDP protocol enabled.

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 a release after 15.6.3m1
Interim mitigation

Apply the vendor patch from Cisco when available. If immediate patching is not feasible, consider disabling LLDP on untrusted network segments or implementing network access control to restrict unauthorized adjacent attackers from reaching the LLDP service.

Recommended fix High confidence

Cisco IOS/IOS XE 15.2(4)E1 or later, 15.2(5)E or later, 15.4(3)S or later, 15.5(3)M or later (specific fixed release depends on your hardware platform; consult Cisco Bug ID CSCvd73664)

  1. 1. Identify the current Cisco IOS/IOS XE/IOS XR version using 'show version' command
  2. 2. Consult Cisco's official security advisory for CVE-2018-0175 (CSCvd73664) to confirm if your specific version is affected
  3. 3. Download the appropriate fixed software version from Cisco's software download center
  4. 4. Plan maintenance window as upgrade requires device downtime
  5. 5. Backup current configuration using 'copy running-config startup-config' or TFTP export
  6. 6. Follow standard Cisco IOS upgrade procedure: copy new image to flash, set boot variable, reload
  7. 7. After reload, verify LLDP is functioning normally and the new version is running with 'show version' and 'show lldp neighbors'
  8. 8. Confirm the fix by ensuring the device is no longer vulnerable to the format string issue in LLDP
Caveat Standard IOS upgrade risks apply - ensure configuration compatibility and backup before upgrading; some legacy features may not be available in newer releases

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

Fix this in iOS Exploited in the wild — priority engagement
  • Consultation8.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,940
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Scan for this in your stack

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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-2018-0175 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