A vulnerability in the Web-Based Reputation Score (WBRS) engine of Cisco AsyncOS Software for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to bypass established web request policies and access blocked content on an affected device. This vulnerability is due to incorrect handling of certain character combinations inserted into a URL. An attacker could exploit this vulnerability by sending crafted URLs to be processed by an affected device. A successful exploit could allow the attacker to bypass the web proxy and access web content that has been blocked by policy.