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Wireless Lan Controller FirmwareOperating system · Cisco

CVE-2017-3854

HIGH · 8.8 CVSS v3.1 Published 2017-03-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
93/100
Remediation priority · Urgent
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 mesh code of Cisco Wireless LAN Controller (WLC) software could allow an unauthenticated, remote attacker to impersonate a WLC in a meshed topology. The vulnerability is due to insufficient authentication of the parent access point in a mesh configuration. An attacker could exploit this vulnerability by forcing the target system to disconnect from the correct parent access point and reconnect to a rogue access point owned by the attacker. An exploit could allow the attacker to control the traffic flowing through the impacted access point or take full control of the target system. This vulnerability affects the following products running a vulnerable version of Wireless LAN Controller software and configured for meshed mode: Cisco 8500 Series Wireless Controller, Cisco 5500 Series Wireless Controller, Cisco 2500 Series Wireless Controller, Cisco Flex 7500 Series Wireless Controller, Cisco Virtual Wireless Controller, Wireless Services Module 2 (WiSM2). Note that additional configuration is needed in addition to upgrading to a fixed release. Cisco Bug IDs: CSCuc98992 CSCuu14804.

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 mesh code of Cisco Wireless LAN Controller allows an unauthenticated remote attacker to impersonate a WLC in a meshed topology due to insufficient authentication of the parent access point. An attacker can force disconnection from the correct parent AP and reconnect to a rogue AP, enabling traffic control or full system compromise.

MitigationUpgrade to a Cisco fixed release and apply the additional configuration changes noted in Cisco Bug IDs CSCuc98992 and CSCuu14804. Ensure mesh authentication settings are properly configured.

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
Wireless Lan Controller FirmwareOperating system
Affected:= 8.0.72.140
Wireless Lan Controller SoftwareOperating system
Affected:= 6.0199.4= 7.41.54= 7.0220.0= 7.0250.0= 16.088.0

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
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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. Check WLC firmware or software version
    Access the WLC CLI (show version) or web interface to determine the running firmware or software version. Compare against the affected versions: 8.0.72.140, 6.0199.4, 7.41.54, 7.0220.0, 7.0250.0, and 16.088.0.
    Affected if The installed version exactly matches one of the listed affected versions.
  2. Verify mesh feature is enabled
    Check the WLC configuration for active mesh WLANs or mesh profile settings. Use CLI command 'show mesh config' or examine the web interface under Wireless > Mesh. Look for any mesh-enabled access points or WLANs.
    Affected if Mesh functionality is actively configured and running on the controller.
  3. Inspect mesh security authentication settings
    Review mesh authentication configuration via CLI 'show mesh security' or through the web interface under Mesh > Security. Verify the authentication method in use (EAP, PSK, etc.) and whether parent AP verification is properly configured.
    Affected if Mesh security settings are either set to defaults or do not enforce strict parent AP authentication and validation.
  4. Review mesh access point associations
    Use CLI command 'show mesh ap' or 'show mesh ap tree' to list all mesh APs and their parent-child relationships. Check for any unexpected APs or anomalous topology changes.
    Affected if Unexpected or rogue APs appear in the mesh topology, or frequent parent reassignments are logged.

You are affected if your WLC firmware/software version matches any of the specific affected versions (8.0.72.140, 6.0199.4, 7.41.54, 7.0220.0, 7.0250.0, or 16.088.0) AND mesh networking is enabled on the controller.

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

Upgrade to a Cisco fixed release and apply the additional configuration changes noted in Cisco Bug IDs CSCuc98992 and CSCuu14804. Ensure mesh authentication settings are properly configured.

Fix this in Wireless Lan Controller Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2017-3854 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