Google Inc. has fixed a flaw in the YouTube code that allowed hackers to redirect users of the popular video-sharing site to adult websites and launch fake pop-up messages.

The search engine giant fixed YouTube's cross-site scripting (XSS) vulnerability two hours after hackers placed codes in the comments section on Sunday to report that Canadian singer Justin Bieber had died in a car accident.

The hackers put codes in YouTube pages devoted to Bieber and fans who clicked on the section were bombarded with pop-up messages ridiculing the teen star and redirecting users to other sites with adult content.

A Google spokesman also said the XSS vulnerability in YouTube is still being studied with the aim of coming up with a stronger protection against hackers, who simply used JavaScript and HTML codes in the attack.

The hacking was initially thought as a virus infection.

YouTube has a huge user traffic. ComScore reported that in May, some 14.6 billion video clips in Google were watched in the U.S. alone. The video clips were mostly from YouTube.

Justin Bieber Google YouTube Hacking