libgd2 - insufficient input sanitising

It was discovered 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.