The remote host is missing an update to libxfont announced via advisory DSA 2293-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202293-1

Tomas Hoger found a buffer overflow in the X.Org libXfont library, which may allow for a local privilege escalation through crafted font files. For the oldstable distribution (lenny), this problem has been fixed in version 1.3.3-2. For the stable distribution (squeeze), this problem has been fixed in version 1.4.1-3. For the unstable distribution (sid), this problem has been fixed in version 1.4.4-1. We recommend that you upgrade your libxfont packages.