Cisco Aironet Access Points Ethernet Wired Clients Denial of Service Vulnerability [CVE-2020-3552]

CVE Number – CVE-2020-3552

A vulnerability in the Ethernet packet handling of Cisco Aironet Access Points (APs) Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. 

The vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by connecting as a wired client to the Ethernet interface of an affected device and sending a series of specific packets within a short time frame. A successful exploit could allow the attacker to cause a NULL pointer access that results in a reload of the affected device.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

Affected Products

  • This vulnerability affects the following Cisco products if they have an Ethernet interface used to provide network access to wired clients, such as a Remote LAN (RLAN) port or Ethernet bridging, and that interface is configured for 802.1q tagging:
    • Aironet 1540 Series APs
    • Aironet 1560 Series APs
    • Aironet 1810, 1815, 1840, and 1850 Series APs
    • Aironet 2800 Series APs
    • Aironet 3800 Series APs


  • There are no workarounds that address this vulnerability.

Fixed Software

  • Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license.

This advisory is available at the following link:

Duncan Newell

Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.

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