VirtualBox 4.2.18

VirtualBox is a general-purpose full virtualizer for x86 hardware. Targeted at server, desktop and embedded use, it is now the only professional-quality virtualization solution that is also Open Source Software.

Some of the features of VirtualBox are:

Modularity. VirtualBox has an extremely modular design with well-defined internal programming interfaces and a client/server design. This makes it easy to control it from several interfaces at once: for example, you can start a virtual machine in a typical virtual machine GUI and then control that machine from the command line, or possibly remotely. VirtualBox also comes with a full Software Development Kit: even though it is Open Source Software, you don't have to hack the source to write a new interface for VirtualBox.
Virtual machine descriptions in XML. The configuration settings of virtual machines are stored entirely in XML and are independent of the local machines. Virtual machine definitions can therefore easily be ported to other computers.

VirtualBox 4.2.18-88780 is a maintenance release. The following items were fixed and/or added:

VMM: properly handle NMIs on Linux hosts with X2APIC enabled
VMM: fixed potential crashes with 64-bit guests on 32-bit hosts (bug #11979)
GUI / seamless: properly handle mouse wheel scroll events
GUI, VBoxManage: when unregistering a VM, also unregister the hard disk images which are used exclusively (bug #10311)
GUI: prevent crashes under certain conditions on X11 hosts
3D: multiscreen fixes (incorrect mouse position, flickers)
3D Support: several fixes for the Windows WDDM video driver (multiscreen, seamless)
Snapshots: made live snapshots work again (bug #9255)
Teleportation: made it work again (bug #9455)
VBoxManage: on snapshot take, --pause is default and --live is for doing live snapshots
VBoxSVC: don't crash on systems with many VLAN interfaces (Solaris hosts only)
Network: after the host resumes from suspend, disconnect and reconnect the virtual network cables to force renewing the DHCP leases for the guests. So far only Mac OS X hosts and Windows hosts (bug #10063).
NAT: on name server changes force a reconnect of the virtual network cable to notify the guest (Mac OS X hosts only)
Mac OS X installer: keep previously installed Extension Packs on VirtualBox upgrade
Linux hosts / guests: Linux 3.11 fixes (bug #12001)
Solaris hosts: fixed a potential kernel panic caused due to unexpected preemption due to logging.
Windows hosts: fixed an issue with USB2 devices being inaccessible when plugged into USB3 ports.
Linux Additions: added PCI device identifier to vboxvideo.ko fixing DRI initialization under certain conditions (bug #11957)
Linux Additions: fixed udev detection in the init script with Linux 3.x kernels