Previously undisclosed bug in all versions of Windows
Just recently, Microsoft detailed the flaw, noting that it exists in Windows' Adobe Type Manager Library, a DLL file used by apps to manage/render fonts from Adobe.
The company denied providing specific details but deemed the issue as 'critical' while noting that it can be triggered by forcing Type Manager Library to improperly handle a specially-crafted font in the Adobe Type 1 PostScript format.
Attack possible by tricking to open malicious documents
Microsoft noted that there are multiple ways to trigger improper handling of the font but the most common way is specially-crafted malicious files.
Basically, the company said, a threat actor can trick you into downloading a compromised file, which, when opened or viewed in the Windows Preview Pane, can let the attacker run malware/ransomware on the targeted PC, steal data from it.