A vulnerability in the management web interface of Cisco Expressway Series could allow an authenticated, remote attacker to perform a directory traversal attack against an affected device. The vulnerability is due to insufficient input validation on the web interface. An attacker could exploit this vulnerability by sending a crafted HTTP request to the web interface. A successful exploit could allow the attacker to bypass security restrictions and access the web interface of a Cisco Unified Communications Manager associated with the affected device. Valid credentials would still be required to access the Cisco Unified Communications Manager interface.