virtualbox - security update

This update fixes an unspecified security issue in VirtualBox related to
guests using bridged networking via WiFi. Oracle no longer provides
information on specific security vulnerabilities in VirtualBox. To still
support users of the already released Debian releases we’ve decided to
update these to the respective 4.1.40 and 4.3.30 bugfix releases.

For the oldstable distribution (wheezy), this problem has been fixed
in version 4.1.40-dfsg-1+deb7u1.

For the stable distribution (jessie), this problem has been fixed in
version 4.3.30-dfsg-1+deb8u1.

For the testing distribution (stretch), this problem has been fixed
in version 4.3.30-dfsg-1.

For the unstable distribution (sid), this problem has been fixed in
version 4.3.30-dfsg-1.

We recommend that you upgrade your virtualbox packages.