Microsoft is considering issuing patches for two severe security vulnerabilities which affect all its enterprise Windows operating systems, the Outlook e-mail system, and the Internet Explorer browser.
Internet security company eEye Digital Security informed Microsoft of the problems, caused by default installations of its products.
Microsoft was told about one of the threats on 16 March and about the other on 29 March. The severity rating of the holes is classed as "high" by eEye, as they allow hackers to execute remote malicious code.
The opportunity for hackers also involved minimal user interaction, said eEye.
No other details of the bugs have been released.
Microsoft said it would have to complete an analysis of the vulnerabilities before it could decide whether to issue patches.