A vulnerability in the URL block page of Cisco Umbrella could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user in a network protected by Umbrella. The vulnerability is due to insufficient validation of input parameters passed to that page. An attacker could exploit this vulnerability by persuading a user of the interface to click a maliciously crafted link.

A successful exploit could allow the attacker to execute arbitrary script code in the context of the interface or access sensitive browser-based information. This vulnerability has been fixed in the current version of Cisco Umbrella. Cisco Umbrella is a cloud service.