The remote host is missing an update to xen-utils announced via advisory DSA 1384-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201384-1

Several local vulnerabilities have been discovered in the Xen hypervisor packages which may lead to the execution of arbitrary code. The Common Vulnerabilities and Exposures project identifies the following problems: CVE-2007-4993 By use of a specially crafted grub configuration file a domU user may be able to execute arbitary code upon the dom0 when pygrub is being used. CVE-2007-1320 Multiple heap-based buffer overflows in the Cirrus VGA extension, provided by QEMU, may allow local users to execute arbitrary code via bitblt heap overflow. For the stable distribution (etch), these problems have been fixed in version 3.0.3-0-3. For the unstable distribution (sid), these problems will be fixed soon. We recommend that you upgrade your xen-utils package.