The remote host is missing an update to libproxy announced via advisory DSA 2571-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202571-1

The Red Hat Security Response Team discovered that libproxy, a library for automatic proxy configuration management, applied insufficient validation to the Content-Length header sent by a server providing a proxy.pac file. Such remote server could trigger an integer overflow and consequently overflow an in-memory buffer. For the stable distribution (squeeze), this problem has been fixed in version 0.3.1-2+squeeze1. For the testing distribution (wheezy), and the unstable distribution (sid), this problem has been fixed in version 0.3.1-5.1. We recommend that you upgrade your libproxy packages.