Microsoft has issued a warning about more vulnerabilities in Windows, including one that allows hackers access through its Virtual Machine (VM) for Java.

Microsoft's VM for Java, which enables Java programs to run on Windows, is in all versions of the operating system since Windows 98.

Eight vulnerabilities have been found in VM that could be triggered by visiting a web page containing malicious Java code.

Microsoft said the most serious of the flaws could enable a website to compromise a user's system and perform actions such as changing data, loading and running programs, and reformatting the hard disk.

According to Microsoft's website the vulnerabilities range from one that is rated "critical" to others that are "important", "moderate" and "low."

It said users should scrap older versions of Java VM and install the latest version.

Users who have Microsoft Outlook Email Security Update are protected, according to the company.