Oracle announced a few minutes ago, August 21st, the immediate availability for download of the VirtualBox 4.1.20 virtualization software for Linux, Mac OS X and Windows platforms.
VirtualBox 4.1.20 comes with compile fixes for the Linux kernel 3.5 RC1 and Linux kernel 3.6 RC1, as well as for the Red Hat Enterprise Linux and CentOS 6.3 distributions.
Moreover, this version brings fixes for the Gentoo Linux operating system, and better mouse integration on the Fedora 17 guests.
Among other interesting changes brought by VirtualBox 4.1.20, we can mention that a snapshots crash was fixed when restoring an old snapshot, and the clipboard is now disabled by default for new virtual machines.
A complete changelog, with all the fixes and improvements, can be found in the official announcement
for Oracle VirtualBox 4.1.20.Download VirtualBox 4.1.20
for Linux right now from Softpedia.