Amarok is an advanced music player.
The Magnatune downloader doesn't quote the "m_currentAlbumFileName" parameter while calling the "unzip" shell command.
A compromised or malicious Magnatune server can remotely execute arbitrary shell code with the rights of the user running Amarok on a client that have previously registered for buying music.
Do not use the Magnatune component of Amarok.
All Amarok users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose ">=media-sound/amarok-1.4.5-r1"