The remote host is missing an update to libpng, libpng3 announced via advisory DSA 498-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20498-1

Steve Grubb discovered a problem in the Portable Network Graphics library libpng which is utilised in several applications. When processing a broken PNG image, the error handling routine will access memory that is out of bounds when creating an error message. Depending on machine architecture, bounds checking and other protective measures, this problem could cause the program to crash if a defective or intentionally prepared PNG image file is handled by libpng. This could be used as a denial of service attack against various programs that link against this library. The following commands will show you which packages utilise this library and whose programs should probably restarted after an upgrade: apt-cache showpkg libpng2 apt-cache showpkg libpng3 The following security matrix explains which package versions will contain a correction. Package stable (woody) unstable (sid) libpng 1.0.12-3.woody.5 1.0.15-5 libpng3 1.2.1-1.1.woody.5 1.2.5.0-6 We recommend that you upgrade your libpng and related packages.