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.
This category represents one of the phyla in the Seven Pernicious Kingdoms vulnerability classification. It includes weaknesses that occur when an application does not properly handle errors that occur during processing. According to the authors of the Seven Pernicious Kingdoms, "Errors and error handling represent a class of API. Errors related to error handling are so common that they deserve a special kingdom of their own. As with 'API Abuse,' there are two ways to introduce an error-related security vulnerability: the most common one is handling errors poorly (or not at all). The second is producing errors that either give out too much information (to possible attackers) or are difficult to handle."
The product does not properly control the allocation and maintenance of a limited resource.