https://www.systemtek.co.uk/2020/09/cisco-ios-xe-software-zone-based-firewall-denial-of-service-vulnerabilities-cve-2020-3421-cve-2020-3480/
Cisco IOS XE Software Zone-Based Firewall Denial of Service Vulnerabilities [CVE-2020-3421 & CVE-2020-3480]