Thanks much for bringing this to our attention. This does appear to be a code defect.
The issue is due to the way we are enumerating the new Web Media Extension Package. This package is not registered as expected causing the list of enumerated codecs to become corrupt. This in turn triggers a double free in the list.
The only workaround currently available is to uninstall the Web Media Extension Package. After uninstalling the package the API should work as expected. Keep in mind that by uninstalling this Package certain audio and video files may not play on your machine.
We will continue to investigate this issue and if possible consider a change to the API or the Web Media Extension Package in a future version of the OS.
Thanks again for reporting this and I do hope the workaround will be sufficient.