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iOSOperating system · Cisco

CVE-2018-0473

HIGH · 8.6 CVSS v3.0 Published 2018-10-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable 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 Precision Time Protocol (PTP) subsystem of Cisco IOS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition of the Precision Time Protocol. The vulnerability is due to insufficient processing of PTP packets. An attacker could exploit this vulnerability by sending a custom PTP packet to, or through, an affected device. A successful exploit could allow the attacker to cause a DoS condition for the PTP subsystem, resulting in time synchronization issues across the network.

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 denial-of-service vulnerability exists in Cisco IOS Software's Precision Time Protocol (PTP) subsystem due to insufficient processing of PTP packets. An unauthenticated remote attacker can send specially crafted PTP packets to cause the PTP subsystem to fail, resulting in time synchronization disruptions across the network.

MitigationApply the relevant Cisco IOS software update when available. If PTP is not required in the environment, consider disabling it. Otherwise, restrict PTP traffic at network boundaries to prevent unauthorized packets from reaching affected devices.

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:= 15.2\(4\)e= 15.2\(5\)

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/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 IOS version
    Execute 'show version' on the device CLI and locate the version string in the output (e.g., 'Version 15.2(5)')
    Affected if The version matches 15.2(4)e or 15.2(5)
  2. Verify if PTP is enabled
    Execute 'show ptp status' to check if Precision Time Protocol is running on the device
    Affected if PTP status shows as 'enabled' or 'running' with an active master clock
  3. Check PTP configuration in running config
    Execute 'show running-config | include ptp' or 'show running-config | begin ptp' to view PTP-related configuration lines
    Affected if PTP configuration commands are present (such as 'ptp mode', 'ptp transport', or PTP interface settings)
  4. Verify PTP port status
    Execute 'show ptp port' to see which interfaces have PTP enabled and their current state
    Affected if Any interfaces show PTP ports in 'LISTENING', 'PASSIVE', or 'MASTER' state indicating active PTP processing
  5. Check for recent PTP-related system messages
    Execute 'show log' or 'show logging' and search for PTP-related error or failure messages, especially those indicating PTP subsystem failures
    Affected if Recent logs contain PTP error messages, resets, or failure notifications indicating the subsystem may already be compromised

The device is affected only if it runs Cisco IOS version 15.2(4)e or 15.2(5) AND has PTP enabled and actively processing PTP packets.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the relevant Cisco IOS software update when available. If PTP is not required in the environment, consider disabling it. Otherwise, restrict PTP traffic at network boundaries to prevent unauthorized packets from reaching affected devices.

Fix this in iOS Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,800
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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-2018-0473 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