CVE-2020-3559: Cisco Aironet Access Point Authentication Flood Denial of Service Vulnerability

Severity: high (CVSS 8.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-09-24 · updated 2026-06-17
Weakness: CWE-400

Description

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 Mobility Express 1800 Access Point Series: 8.5(151.0), 17.2.0.26
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

How to fix

Upgrade to a fixed version: Cisco Access Points 16.12.4a; Cisco Business Access Points 10.1.1.0; Cisco Wireless Lan Controller 8.10.112.0. Check the vendor advisory for mitigations.

References

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