The remote host is missing an update to libarchive announced via advisory DSA 2413-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202413-1

Two buffer overflows have been discovered in libarchive, a library providing a flexible interface for reading and writing archives in various formats. The possible buffer overflows while reading is9660 or tar streams allow remote attackers to execute arbitrary code depending on the application that makes use of this functionality. For the stable distribution (squeeze), this problem has been fixed in version 2.8.4-1+squeeze1. For the testing (wheezy) and unstable (sid) distributions, this problem has been fixed in version 2.8.5-5. We recommend that you upgrade your libarchive packages.