CVE-2020-3510: Cisco IOS XE

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

A vulnerability in the Umbrella Connector component of Cisco IOS XE Software for Cisco Catalyst 9200 Series Switches could allow an unauthenticated, remote attacker to trigger a reload, resulting in a denial of service condition on an affected device. The vulnerability is due to insufficient error handling when parsing DNS requests. An attacker could exploit this vulnerability by sending a series of malicious DNS requests to an Umbrella Connector client interface of an affected device. A successful exploit could allow the attacker to cause a crash of the iosd process, which triggers a reload of the affected device.

Affected products

• Cisco IOS XE: version 16.12.1 only; version 16.12.2 only; version 17.1.1 only

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