The remote host is missing an update to freetype announced via advisory DSA 2328-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202328-1

It was discovered that missing input sanitising in Freetype's glyph handling could lead to memory corruption, resulting in denial of service or the execution of arbitrary code. For the oldstable distribution (lenny), this problem has been fixed in version 2.3.7-2+lenny7. For the stable distribution (squeeze), this problem has been fixed in version 2.4.2-2.1+squeeze2. For the unstable distribution (sid), this problem has been fixed in version 2.4.7-1. We recommend that you upgrade your freetype packages.