vboxguest: module verification failed: signature and/or required key missing - tainting kernel

[FranzS]

I've found the error Message mentioned above in my syslog of an Ubuntu 16.04 X64 Server) , see below.

May 14 12:00:03 fortuna kernel: [    7.962773] EXT4-fs (dm-0): re-mounted. Opts: errors=remount-ro
May 14 12:00:03 fortuna kernel: [    8.354372] vboxguest: module verification failed: signature and/or required key missing - tainting kernel
May 14 12:00:03 fortuna kernel: [    8.371889] piix4_smbus 0000:00:07.0: SMBus base address uninitialized - upgrade BIOS or use force_addr=0xaddr
May 14 12:00:03 fortuna kernel: [    8.397995] vgdrvHeartbeatInit: Setting up heartbeat to trigger every 2000 milliseconds
May 14 12:00:03 fortuna kernel: [    8.398075] input: Unspecified device as /devices/pci0000:00/0000:00:04.0/input/input6
May 14 12:00:03 fortuna kernel: [    8.410875] vboxguest: misc device minor 55, IRQ 20, I/O port d020, MMIO at 00000000f0400000 (size 0x400000)
May 14 12:00:03 fortuna kernel: [    8.410879] vboxguest: Successfully loaded version 5.0.20 (interface 0x00010004)
May 14 12:00:03 fortuna kernel: [    8.469950] [drm] Initialized drm 1.1.0 20060810

So on one hand an error, but on the other hand it works. I've googled a little and found out that it has to do with Kernel Module signing. Is there any way to fix this?

See also this thread in the Support Forum: ​https://forums.virtualbox.org/viewtopic.php?f=3&t=77687