1. Install VLC 0.6.8d from http://download.videolan.org/pub/videolan/vlc/0.8.6d/win32/vlc-0.8.6d-win32.exe
2. Go to data:text/html,<embed type="application/x-vlc-plugin"><embed type="application/x-vlc-plugin">
3. Reload the page until crash occurs
The crash is in free() inside VLC code. The bug happens only in WebKit2, not in WebKit1. It looks like this happens in Firefox and Chrome, too, but it's harder to detect there due to out-of-process plugins.
WebKit1 works around this VLC bug using the PluginQuirkDontAllowMultipleInstances quirk.
Note that the crash does not occur with the most recent version of VLC, 1.1.9. I haven't tested any other versions.