The remote host is missing an update to squid3 announced via advisory DSA 1843-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201843-1

It was discovered that squid3, a high-performance proxy caching server for web clients, is prone to several denial of service attacks. Due to incorrect bounds checking and insufficient validation while processing response and request data an attacker is able to crash the squid daemon via crafted requests or responses. The squid package in the oldstable distribution (etch) is not affected by this problem. For the stable distribution (lenny), this problem has been fixed in version 3.0.STABLE8-3+lenny1. For the testing distribution (squeeze) and the unstable distribution (sid), this problem will be fixed soon. We recommend that you upgrade your squid3 packages.