The bug report, posted to GitHub by user Robo2Bobo, states that it became possible to crash the screensaver and unlock the desktop via the virtual keyboard. Robo2Bobo then explained that this was found because “A few weeks ago, my kids wanted to hack my Linux desktop, so they typed and clicked everywhere, while I was standing behind them looking at them play... when the screensaver core dumped and they actually hacked their way in!”
Evidently, this issue affects any Linux distribution using Cinnamon 4.2+ and any software using libcaribou, an on-screen keyboard (OSK) component, according to Linux Mint lead developer Clement Lefebvre. However, there is now a fix for Linux Mint, so it is time to update if you believe you are afflicted. Also, a setting to disable the on-screen keyboard is in the works for Mint, so vulnerabilities like this can be solved in the short term easily. The moral of the story? Hackers come in all shapes, sizes and apparently now ages, too.