Microsoft has issued a "critical" warning over a newly-discovered flaw in Windows.
In a security advisory, the company warned of a loophole that could be used by malicious hackers to steal private information or hijack computers.
The bug potentially affects every user of the Internet Explorer web browser - around 900 million people worldwide.
Microsoft has issued a software patch to defend against attacks, and said it was working to develop a long-term fix. More...