If you’re a Twitter user, the site has been exposed to a serious JavaScript exploit. The JavaScript onMouseOver exploit happens when you hover your mouse over a tweet. It will then redirect your browser to a website that contains malicious code, or adult websites. Apparently it also creates messages that you didn’t write.

The flaw currently only affects twitter.com, so if you’re tweeting using third party programs, you’re fine. Twitter has been working on a fix and apparently it has just been patched.

[sophos]