The remote host is missing an update to libgd2 announced via advisory DSA 1117-1. It was discoverd that the GD graphics library performs insufficient checks of the validity of GIF images, which might lead to denial of service by tricking the application into an infinite loop.
For the stable distribution (sarge) this problem has been fixed in version 2.0.33-1.1sarge1. For the unstable distribution (sid) this problem has been fixed in version 2.0.33-5. We recommend that you upgrade your libgd2 packages. https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201117-1