The remote host is missing an update to squid3 announced via advisory DSA 1732-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201732-1

Joshua Morin, Mikko Varpiola and Jukka Taimisto discovered an assertion error in squid3, a full featured Web Proxy cache, which could lead to a denial of service attack. For the stable distribution (lenny), this problem has been fixed in version 3.0.STABLE8-3, which was already included in the lenny release. For the oldstable distribution (etch), this problem has been fixed in version 3.0.PRE5-5+etch1. For the testing distribution (squeeze) and the unstable distribution (sid), this problem has been fixed in version 3.0.STABLE8-3.