A vulnerability in the web-based management interface of Session Initiation Protocol (SIP) Software for Cisco IP Phone 8800 Series could allow an authenticated, remote attacker to write arbitrary files to the filesystem. The vulnerability is due to insufficient input validation and file-level permissions. An attacker could exploit this vulnerability by uploading invalid files to an affected device. A successful exploit could allow the attacker to write files in arbitrary locations on the filesystem. This vulnerability affects Cisco IP Phone 8800 Series products running a SIP Software release prior to 11.0(5) for Wireless IP Phone 8821 and 8821-EX; and 12.5(1)SR1 for the IP Conference Phone 8832 and the rest of the IP Phone 8800 Series.