All versions of Windows hit by "critical" security vulnerabilities

Microsoft has fixed a critical security vulnerability affecting all supported versions of Windows.

The company said in a security advisory that all users of Windows 10 and earlier should patch as soon as possible to prevent attackers from exploiting a flaw in how the operating system handles graphics and fonts.

The patch fixes four separate vulnerabilities -- the worst of which could let an attacker install malware on an affected computer. The flaw is not thought to have been actively exploited in the wild, the company said.