Missing file and path validation in the ringtone upload function of the Akuvox R50P VoIP phone 50.0.6.156 allows an attacker to upload a manipulated ringtone file, with an executable payload (shell commands within the file) and trigger code execution.
https://www.sit.fraunhofer.de/fileadmin/dokumente/CVE/Advisory_Akuvox_R50P.pdf