VirtualBox is a usual-purpose full virtualizer for x86 tools. Targeted at server, desktop, and installed application, it is currently the sole professional-quality virtualization solution that is more Open Source Software.
The following Changed Added
GUI: mouse events did not reach host windows behind the transparent VM window.
Audio: fixed accidental crashes when using the AC'97 sound emulation.
Audio: fixed crash when default input or output devices have changed.
Audio: fixed recording when using the ALSA backend.
Audio: fixed handle leak when using the OSS backend.
E1000: fixed a crash related to VLAN traffic over the internal network (5.1.26 regression).
NAT: apply --natbindip1 to TCP connections.
OVF: when importing an appliance with XHCI controller, don't add an OHCI controller.
Mac OS X hosts: fixed a GUI crash if Spotlight is used from file dialogs (5.1.20 regression).
Linux hosts fixed to create fixed sized VDI images.
Linux hosts / guests: fixes for Linux 4.4 of openSUSE Leap 42.3.
Bridged networking: align outgoing packet at the word boundary, preventing Windows host crash in MsLbfoProvider.
Linux Additions: kernel drm driver support for custom EL7 Linux 3.10 kernel.
Solaris Additions: hide an informational message on the bootup console.