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Ios XeOperating system · Cisco

CVE-2018-0165

HIGH · 7.4 CVSS v3.0 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 →
79/100
Remediation priority · High
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 Internet Group Management Protocol (IGMP) packet-processing functionality of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to exhaust buffers on an affected device, resulting in a denial of service (DoS) condition, aka a Memory Leak. The vulnerability is due to the affected software insufficiently processing IGMP Membership Query packets that are sent to an affected device. An attacker could exploit this vulnerability by sending a large number of IGMP Membership Query packets, which contain certain values, to an affected device. A successful exploit could allow the attacker to exhaust buffers on the affected device, resulting in a DoS condition that requires the device to be reloaded manually. This vulnerability affects: Cisco Catalyst 4500 Switches with Supervisor Engine 8-E, if they are running Cisco IOS XE Software Release 3.x.x.E and IP multicast routing is configured; Cisco devices that are running Cisco IOS XE Software Release 16.x, if IP multicast routing is configured. Cisco Bug IDs: CSCuw09295, CSCve94496.

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 memory leak vulnerability in Cisco IOS XE Software's IGMP packet-processing allows an adjacent, unauthenticated attacker to send specially crafted IGMP Membership Query packets that exhaust buffers on affected devices, causing denial of service requiring manual reload. The vulnerability only affects devices with IP multicast routing configured.

MitigationApply Cisco software updates for IOS XE (Bug IDs CSCuw09295, CSCve94496). If updates are unavailable, consider disabling IP multicast routing on affected devices if not operationally required, or implement network segmentation to restrict adjacent attacker access.

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:= 15.2\(3\)e= 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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:A/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. Verify the device runs Cisco IOS XE
    Run 'show version' and look for 'IOS XE' in the output
    Affected if The device is not running Cisco IOS XE (this CVE does not apply)
  2. Check the IOS XE version number
    Run 'show version' and locate the version string (e.g., 15.2(3)e, 16.3.3)
    Affected if Version is exactly 15.2(3)e or denali-16.3.3 (other versions may have separate advisories)
  3. Confirm IP multicast routing is enabled
    Run 'show ip multicast' or 'show running-config | include ip multicast' to check if multicast routing is configured
    Affected if IP multicast routing is not configured (the vulnerability only affects devices with this feature enabled)
  4. Check IGMP configuration
    Run 'show ip igmp interface' to see IGMP-enabled interfaces
    Affected if IGMP is actively running on any interface (the crafted packets target IGMP processing)

Device is affected only if it runs IOS XE version 15.2(3)e or denali-16.3.3 AND has IP multicast routing 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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Cisco software updates for IOS XE (Bug IDs CSCuw09295, CSCve94496). If updates are unavailable, consider disabling IP multicast routing on affected devices if not operationally required, or implement network segmentation to restrict adjacent attacker access.

Fix this in Ios Xe Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,980
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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-2018-0165 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
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  • Version or environment caveats, and links to real fixes
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