dbcve.org
Aironet Access Point FirmwareOperating system · Cisco

CVE-2017-3873

HIGH · 7.5 CVSS v3.0 Published 2017-05-16
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
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 Plug-and-Play (PnP) subsystem of the Cisco Aironet 1800, 2800, and 3800 Series Access Points running a Lightweight Access Point (AP) or Mobility Express image could allow an unauthenticated, adjacent attacker to execute arbitrary code with root privileges. The vulnerability is due to insufficient validation of PnP server responses. The PnP feature is only active while the device does not contain a configuration, such as a first time boot or after a factory reset has been issued. An attacker with the ability to respond to PnP configuration requests from the affected device can exploit the vulnerability by returning malicious PnP responses. If a Cisco Application Policy Infrastructure Controller - Enterprise Module (APIC-EM) is available on the network, the attacker would need to exploit the issue in the short window before a valid PnP response was received. If successful, the attacker could gain the ability to execute arbitrary code with root privileges on the underlying operating system of the device. Cisco has confirmed that the only vulnerable software version is 8.3.102.0. Cisco Bug IDs: CSCvb42386.

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 buffer overflow vulnerability exists in the Plug-and-Play (PnP) subsystem of Cisco Aironet 1800, 2800, and 3800 Series Access Points running vulnerable Lightweight AP or Mobility Express images. The PnP server response validation is insufficient, allowing an adjacent attacker with the ability to respond to PnP configuration requests to inject and execute arbitrary code with root privileges. The vulnerability is only exploitable when the device has no configuration (first-time boot or post-factory reset). Cisco confirms only version 8.3.102.0 is affected.

MitigationUpgrade to a patched Cisco firmware version beyond 8.3.102.0. Until then, ensure affected access points complete initial configuration promptly and monitor for unauthorized devices on the network segment that could intercept PnP requests during the vulnerable window.

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
Aironet Access Point FirmwareOperating system
Affected:= 8.3_102.0

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:A/AC:H/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. Identify the access point model
    Check the device model number on the physical unit or via CLI command 'show version' to confirm it is a Cisco Aironet 1800, 2800, or 3800 Series Access Point
    Affected if Device is NOT one of these three series models
  2. Check the firmware version
    Run 'show version' or 'show inventory' on the AP CLI to retrieve the installed firmware version. Look for version string '8.3.102.0' or '8.3_102.0'
    Affected if Firmware version is NOT exactly 8.3.102.0 (no other versions are affected)
  3. Verify the image type
    Run 'show version' to confirm the AP is running a Lightweight AP (LAP) image or Mobility Express (ME) image rather than a autonomous image
    Affected if AP is NOT running Lightweight AP or Mobility Express image
  4. Determine the configuration state
    Check if the AP has an existing configuration. Run 'show running-config' or attempt to access the GUI at the AP IP address. A fresh device will show default settings or prompt for initial configuration
    Affected if AP already has a complete configuration applied (the vulnerability only applies to first-time boot or post-factory reset state)

All four conditions must be true simultaneously: Aironet 1800/2800/3800 series, firmware exactly 8.3.102.0, Lightweight AP or Mobility Express image, and device has no configuration (factory default state). If any condition fails, the device is not affected by this specific CVE.

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 patched Cisco firmware version beyond 8.3.102.0. Until then, ensure affected access points complete initial configuration promptly and monitor for unauthorized devices on the network segment that could intercept PnP requests during the vulnerable window.

Fix this in Aironet Access Point 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-2017-3873 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
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  • Version or environment caveats, and links to real fixes
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