dbcve.org
Ios XeOperating system · Cisco

CVE-2018-0177

HIGH · 7.5 CVSS v3.1 Published 2018-03-28
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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 IP Version 4 (IPv4) processing code of Cisco IOS XE Software running on Cisco Catalyst 3850 and Cisco Catalyst 3650 Series Switches could allow an unauthenticated, remote attacker to cause high CPU utilization, traceback messages, or a reload of an affected device that leads to a denial of service (DoS) condition. The vulnerability is due to incorrect processing of certain IPv4 packets. An attacker could exploit this vulnerability by sending specific IPv4 packets to an IPv4 address on an affected device. A successful exploit could allow the attacker to cause high CPU utilization, traceback messages, or a reload of the affected device that leads to a DoS condition. If the switch does not reboot when under attack, it would require manual intervention to reload the device. This vulnerability affects Cisco Catalyst 3850 and Cisco Catalyst 3650 Series Switches that are running Cisco IOS XE Software Release 16.1.1 or later, until the first fixed release, and are configured with an IPv4 address. Cisco Bug IDs: CSCvd80714.

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 vulnerability in the IPv4 processing code of Cisco IOS XE Software on Catalyst 3850 and 3650 series switches allows unauthenticated remote attackers to send specific IPv4 packets to an affected device's IPv4 address, causing high CPU utilization, traceback messages, or device reload leading to denial of service.

MitigationApply the Cisco firmware update from CSCvd80714 to affected devices running IOS XE 16.1.1 or later, or implement network-level filtering to block malicious IPv4 packets destined to the affected switch interfaces.

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
Ios XeOperating system
Affected:= denali-16.3.1= denali-16.3.3

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

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 device model
    Run 'show version' or check the device chassis to confirm it is a Catalyst 3850 or Catalyst 3650 series switch
    Affected if The device is NOT a Catalyst 3850 or 3650 series switch (if it is a different model, it is not affected)
  2. Check the IOS XE version
    Run 'show version' and locate the IOS XE software version string (typically shows as 'Version 16.3.x')
    Affected if The installed version is exactly denali-16.3.1 or denali-16.3.3 (these are the only affected versions listed)
  3. Confirm IPv4 processing is active
    Run 'show ip interface brief' to verify IPv4 addresses are configured and interfaces are up
    Affected if IPv4 is not configured on any interface (the vulnerability requires IPv4 to be processing traffic)
  4. Look for exploitation symptoms
    Run 'show processes cpu history' to check for high CPU usage spikes, and check logs for traceback messages or unexpected reloads
    Affected if Device exhibits high CPU utilization, traceback messages in logs, or has experienced unexplained reloads

The device is affected only if it is a Catalyst 3850 or 3650 series switch running IOS XE version 16.3.1 or 16.3.3 with IPv4 enabled and processing traffic.

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 Cisco firmware update from CSCvd80714 to affected devices running IOS XE 16.1.1 or later, or implement network-level filtering to block malicious IPv4 packets destined to the affected switch interfaces.

Fix this in Ios Xe Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2018-0177 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