The remote host is missing an update to php5 announced via advisory DSA 2492-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202492-1

The Phar extension for PHP does not properly handle crafted tar files, leading to a heap-based buffer overflow. PHP applications processing tar files could crash or, potentially, execute arbitrary code. In addition, this update addresses a regression which caused a crash when accessing a global object that is returned as $this from __get. For the stable distribution (squeeze), this problem has been fixed in version 5.3.3-7+squeeze13. For the testing distribution (wheezy) and the unstable distribution (sid), this problem has been fixed in version 5.4.4~rc1-1. We recommend that you upgrade your php5 packages.