Microsoft is warning people of a potentially serious vulnerability in its ASP.Net framework used to create Web sites.

The hole affects all versions of the.Net
framework, including the latest, 4.0, which was released in April.

The vulnerability, which is being called "Cross-Site Scripting" (XSS), allows attackers to inject malicious code into Web pages.

Microsoft said it had not yet seen any attacks exploiting the vulnerability, but it was