Synaesthesia 2.1 and earlier, and possibly other versions, when installed setuid root, does not drop privileges before processing configuration and mixer files, which allows local users to read arbitrary files.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2005-0071
http://www.securityfocus.com/bid/12546
http://www.debian.org/security/2005/dsa-681