Skype has been forced to turn off a video-sharing feature in its software because it could be misused to launch a self-copying worm attack against Skype users, according to security researchers.

A bug in the software, which was first reported last week, stems from the way Skype uses an Internet Explorer component to render HTML.

Skype's video-sharing feature allows users to share videos hosted on two sites - and - while chatting with other Skype users.

Last week security researcher Aviv Raff showed how attackers could exploit the bug to run unauthorised software on a Skype user's PC. But on Tuesday, the security researcher said the flaw was more serious than he'd first thought. It can "be triggered by simply visiting a website, or clicking on a link from your instant messaging application," he wrote in a blog posting, "Which basically means that this vulnerability is now wormable."

Skype appeared to have pulled the video feature from its client software on Tuesday as a result of the bug. Users who attempted to click on the "videos" button within a chat window were greeted with a message that the feature was unavailable "because of some security concerns."