Summary
The remote host is missing an update to qemu-kvm
announced via advisory USN-863-1.
Solution
The problem can be corrected by upgrading your system to the following package versions:
Ubuntu 9.10:
qemu-kvm 0.11.0-0ubuntu6.3
After a standard system upgrade you need to restart any QEMU guests to effect the necessary changes.
https://secure1.securityspace.com/smysecure/catid.html?in=USN-863-1
Insight
It was discovered that QEMU did not properly setup the virtio networking features available to its guests. A remote attacker could exploit this to crash QEMU guests which use virtio networking on Linux kernels earlier than 2.6.26.
