This discovery was made by the folks at McAfee where they discovered that activating Cortana on a locked Windows 10 PC, hackers could actually trick the digital assistant into launching a contextual menu that could be used to execute bits of code.
This means that the hacker could get malicious software to run on the PC without having to unlock it, or they could even use it to reset a Windows account password which means that they could then gain access to the computer and its contents.
This problem is due to the fact that despite the computer being locked, Cortana is always on the listen for commands. Indexing also means that files are accessible in the search function that Cortana uses.
The good news is that Microsoft has since dealt with the issue in the Patch Tuesday update, so if you want to avoid any nasty surprises, then perhaps you’ll want to update your computer ASAP.