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Ios XeOperating system · Cisco

CVE-2020-3489

HIGH · 7.4 CVSS v3.1 Published 2020-09-24
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
Multiple vulnerabilities in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol processing of Cisco IOS XE Software for Cisco Catalyst 9800 Series Wireless Controllers could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition of an affected device. These vulnerabilities are due to insufficient validation of CAPWAP packets. An attacker could exploit these vulnerabilities by sending a malformed CAPWAP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to crash and reload, resulting in a DoS condition on the affected device.

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 vulnerabilities exist in the CAPWAP (Control and Provisioning of Wireless Access Points) protocol processing component of Cisco IOS XE Software for Catalyst 9800 Series Wireless Controllers. These vulnerabilities stem from insufficient validation of incoming CAPWAP packets, allowing an unauthenticated adjacent attacker to send malformed CAPWAP packets that trigger a device crash and reload, resulting in denial of service.

MitigationApply the relevant Cisco IOS XE software update for CVE-2020-3489. In the interim, restrict physical/adjacent network access to the CAPWAP management interface and implement network segmentation to limit exposure to adjacent attackers.

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:= 16.12.1

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
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/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. Identify the device model
    Verify the hardware is a Cisco Catalyst 9800 Series Wireless Controller (9800-CL, 9800-L, 9800-SW, 9800 Embedded Wireless Controller for Catalyst 9000 switches)
    Affected if Device is not a Catalyst 9800 Series Wireless Controller
  2. Confirm the operating system
    Check that the device runs Cisco IOS XE software (show version command displays 'IOS XE' in the OS description)
    Affected if Device does not run Cisco IOS XE
  3. Check the IOS XE version
    Run 'show version' and locate the version number in the output. Compare the exact version to the affected range.
    Affected if IOS XE version equals 16.12.1 exactly
  4. Verify CAPWAP is enabled
    Run 'show capwap summary' or 'show wireless capwap summary' to confirm CAPWAP protocol processing is active
    Affected if CAPWAP protocol processing is enabled and running
  5. Assess network exposure
    Review the interface configuration for the AP management/CAPWAP interface (typically the management VLAN interface) and determine if it is accessible to unauthenticated adjacent attackers on the physical or Layer 2 network
    Affected if CAPWAP management interface is accessible to unauthenticated adjacent network attackers

A device is affected if it is a Catalyst 9800 Series Wireless Controller running Cisco IOS XE version 16.12.1 with CAPWAP enabled and the CAPWAP interface is reachable by unauthenticated adjacent attackers.

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 XE software update for CVE-2020-3489. In the interim, restrict physical/adjacent network access to the CAPWAP management interface and implement network segmentation to limit exposure to adjacent attackers.

Fix this in Ios Xe Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,800
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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-2020-3489 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