Microsoft has warned of a vulnerability that affects all versions of the Internet Explorer web browser.
Hackers can use the flaw to take control of a computer, Microsoft said in an advisory on Wednesday.
"Microsoft is investigating new, public reports of a vulnerability in all supported versions of Internet Explorer," said the advisory. "The main impact of the vulnerability is remote code execution."
The memory corruption flaw is exploited in the Metasploit security security tool kit, according to a Microsoft blog post on Wednesday.
Microsoft recommended that people use Protected Mode in IE, as well as a number of workarounds.