GHSA-HW27-4V2Q-5QFF Algernon: Auto-refresh SSE event server sets Access-Control-Allow-Origin: *

Summary The SSE event server's Access-Control-Allow-Origin response header was hardcoded to the wildcard regardless of the caller's Origin. Because EventSource does not preflight and does not send cookies, the wildcard is sufficient to let any third-party page the developer visits open a...