External WebId security issue

Tim Berners-Lee @timbl mai 14 16:11
Intersting: Trying to register a new account with an external webid I get an nmessage saying linked acounts are not supported?

Alain Bourgeois @bourgeoa mai 14 16:18
@timbl it has been removed by @michielbdejong and I don't now why solid/node-solid-server#1566

Tim Berners-Lee @timbl mai 14 16:40
I assume it was a security thing? I wonder how many accountes there are with linked owners

Tim Berners-Lee @timbl mai 14 16:46
Anyone else know?

Michiel de Jong @michielbdejong 09:27
Yes, it was a security thing. We can only re-activate it if we fix the way aliases work, first. With the current code, it was possible to steal any existing username on the same server and make it a local alias of the newly created account. So you would need to add a check to make sure the external webid is not local!

@michielbdejong
Is aliases owl:sameAs ?
Is the security issue related to CORS ?