The remote host is missing an update to squid3 announced via advisory DSA 2381-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202381-1

It was discovered that the IPv6 support code in Squid does not properly handle certain DNS responses, resulting in deallocation of an invalid pointer and a daemon crash. The squid package and the version of squid3 shipped in lenny lack IPv6 support and are not affected by this issue. For the stable distribution (squeeze), this problem has been fixed in version 3.1.6-1.2+squeeze2. For the testing distribution (wheezy) and the unstable distribution (sid), this problem has been fixed in version 3.1.18-1. We recommend that you upgrade your squid3 packages.