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http://fetch.spec.whatwg.org/#access-control-allow-origin-response-header says Access-Control-Allow-Origin = "Access-Control-Allow-Origin" ":" origin-list-or-null | "*" Since http://fetch.spec.whatwg.org/#resource-sharing-check fails when more than one origin are specified, I think the syntax should be changed to only allow one origin. Apparently the Origin header should get the same treatment.
As far as I know that was done to use the same language from the linked [ORIGIN] page. But it would be nice to rid of it, fsck the linked spec. :D
This bug refers to "fetch" not CORS. Closing without spec changes. Access control check behavior forbids multiple origins implictly. http://www.w3.org/2011/webappsec/minutes/webappsec-minutes-27-Aug-2013.html