The remote host is missing an update to avahi announced via advisory DSA 2174-1.

For the oldstable distribution (lenny), this problem has been fixed in version 0.6.23-3lenny3. For the stable distribution (squeeze), this problem has been fixed in version 0.6.27-2+squeeze1. For the testing (wheezy) and unstable distribution (sid), this problem has been fixed in version 0.6.28-4. We recommend that you upgrade your avahi packages. https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202174-1

It was discovered that avahi, an implementation of the zeroconf protocol, can be crashed remotely by a single UDP packet, which may result in a denial of service.