GHSA-v3j7-r9gq-3gjw Electron: Custom protocol with supportFetchAPI but not corsEnabled allows cross-origin reads

• npm electron: >= 42.0.0-alpha.1, < 42.0.0 → fixed in 42.0.0 • npm electron: >= 41.0.0-alpha.1, < 41.4.0 → fixed in 41.4.0 • npm electron: >= 40.0.0-alpha.1, < 40.9.3 → fixed in 40.9.3 • npm electron: < 39.8.10 → fixed in 39.8.10

Impact A custom scheme registered with `supportFetchAPI: true` but without `corsEnabled: true` was not subject to CORS enforcement. A page loaded from a remote origin could therefore `fetch()` or `XMLHttpRequest` that scheme cross-origin and read the full response body, rather than the read being blocked. Apps that serve sensitive data from such a scheme and load remote or untrusted content in a renderer are affected. Apps that set `corsEnabled: true`, or that do not load untrusted content, are not affected. Workarounds Set `corsEnabled: true` on schemes that must enforce CORS, and validate the request `Origin` in your protocol handler before returning sensitive data. Fixed Versions • `42.0.0` • `41.4.0` • `40.9.3` • `39.8.10` For more information If you have any questions or comments about this advisory, email Electron at [email protected]