The remote host is missing an update to netpbm-free announced via advisory DSA 426-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20426-1

netpbm is graphics conversion toolkit made up of a large number of single-purpose programs. Many of these programs were found to create temporary files in an insecure manner, which could allow a local attacker to overwrite files with the privileges of the user invoking a vulnerable netpbm tool. For the current stable distribution (woody) these problems have been fixed in version 2:9.20-8.4. For the unstable distribution (sid) these problems have been fixed in version 2:9.25-9. We recommend that you update your netpbm-free package.