The remote host is missing an update to mumble announced via advisory DSA 2411-1.
It was discovered that mumble, a VoIP client, does not probably manage permission on its user-specific configuration files, allowing other local users on the system to access them. For the stable distribution (squeeze), this problem has been fixed in version 1.2.2-6+squeeze1. For the testing distribution (wheezy) and the unstable distribution (sid), this problem has been fixed in version 1.2.3-3. We recommend that you upgrade your mumble packages.