GHSA-MRHX-6PW9-Q5FH PhoenixStorybook has cross-session PubSub topic injection via URL parameter

Summary The storybook iframe LiveView accepts a PubSub topic from the URL query string and broadcasts its own pid onto that topic with no check that the topic belongs to the current session. Any unauthenticated visitor who knows or guesses another user's playground topic can hijack the...