CVE-2020-3359: Cisco IOS XE

High severity, CVSS 8.6. EPSS: 1.5% chance of exploitation in the next 30 days.

A vulnerability in the multicast DNS (mDNS) feature of Cisco IOS XE Software for Cisco Catalyst 9800 Series Wireless Controllers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper validation of mDNS packets. An attacker could exploit this vulnerability by sending a crafted mDNS packet to an affected device. A successful exploit could cause a device to reload, resulting in a DoS condition.

Affected products

• Cisco IOS XE: version 16.12.1 only

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