Cisco 8800 phones with software 11.0(1) do not properly enforce mounted-filesystem permissions, which allows local users to write to arbitrary files by leveraging shell access, aka Bug ID CSCuz03014.
http://www.securitytracker.com/id/1036138
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160620-ipp