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Ios XeOperating system · Cisco

CVE-2020-3497

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

This vulnerability exists in the CAPWAP protocol processing of Cisco IOS XE Software for Catalyst 9800 Series Wireless Controllers. An unauthenticated, adjacent attacker can send malformed CAPWAP packets to an affected device, which due to insufficient validation causes the device to crash and reload, resulting in a denial of service.

MitigationApply the relevant Cisco IOS XE software update for the Catalyst 9800 Series when available. In the interim, restrict network access to the wireless controller management and CAPWAP ports to trusted segments to reduce adjacent attack surface.

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. Confirm device is a Catalyst 9800 Series Wireless Controller
    Execute 'show version' or 'show inventory' and verify the hardware model is a Catalyst 9800 series (e.g., C9800-40, C9800-80, C9800-L)
    Affected if The device is not a Catalyst 9800 Series controller - this vulnerability only affects that product line
  2. Check the Cisco IOS XE software version
    Execute 'show version' and locate the IOS XE version string (e.g., 'Version 16.12.1')
    Affected if The installed version is exactly 16.12.1 - this is the only version listed as affected per the CVE
  3. Verify CAPWAP protocol is enabled
    Execute 'show capwap summary' or check that wireless management interfaces are configured and active
    Affected if CAPWAP is active - the vulnerability exists in CAPWAP protocol processing, so the service must be running for the flaw to apply
  4. Assess network accessibility to CAPWAP and management ports
    Review access control lists, VLAN configurations, and network segment placement to determine if an adjacent attacker can reach the controller on ports 5246/5247 (CAPWAP) and 443/22 (management)
    Affected if The CAPWAP and management interfaces are reachable from untrusted network segments - an adjacent attacker requires network access to send malformed CAPWAP packets

The environment is affected if it is a Catalyst 9800 Series Wireless Controller running exactly IOS XE 16.12.1 with CAPWAP enabled and accessible to adjacent attackers on the network.

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 the Catalyst 9800 Series when available. In the interim, restrict network access to the wireless controller management and CAPWAP ports to trusted segments to reduce adjacent attack surface.

Fix this in Ios Xe Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,640
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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-2020-3497 in production — separate from our analysis above.

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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
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