It looks like some Linux distributions have a considerable security hole, with security researchers from the Cybersecurity Group at Polytechnic University of Valencia (UPV) in Spain finding an incredibly easy way to hack into numerous Linux distributions.
The researchers found that by using the Grub2 bootloader, immediately bypasses the lock screen, initiates the "Grub rescue shell" and then grants users the ability to access the system for whatever they need. The team found that pressing the backspace key 28 times triggers a memory error, which then displays the rescue shell. This isn't a massive threat as it means someone has to have physical access to your Linux-based machine, but still - this is quite serious, and considering the security hole wasn't found until now, is shocking to say the least.
Ubuntu, Red Hat, and Debian have all released security patches - so these Linux distributions should now be safe.