CVE-2020-3559: Cisco Access Points

High severity, CVSS 8.6. EPSS: 1.4% chance of exploitation in the next 30 days.

A vulnerability in Cisco Aironet Access Point (AP) Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to improper handling of clients that are trying to connect to the AP. An attacker could exploit this vulnerability by sending authentication requests from multiple clients to an affected device. A successful exploit could allow the attacker to cause the affected device to reload.

Affected products

• Cisco Access Points: before 16.12.4a (fixed in 16.12.4a)
• Cisco Aironet Access Point Software: version 8.5(151.0) only; version 17.2.0.26 only
• Cisco Business Access Points: from 10.0, before 10.1.1.0 (fixed in 10.1.1.0)
• Cisco Wireless Lan Controller: from 8.9, before 8.10.112.0 (fixed in 8.10.112.0)

Published 2020-09-24. Last modified 2026-06-17.