Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to versions 42.11.3, 43.7.0, 44.3.0, and 45.0.0-alpha.5, requests to open external protocol URLs could be attributed to a document other than the one that initiated them, causing the requestingUrl passed to session.setPermissionRequestHandler to identify trusted content for a launch requested by untrusted content. An application that grants openExternal based on the requesting origin and allows untrusted content to open or navigate windows could therefore allow that content to launch an OS-registered external application. This issue is fixed in versions 42.11.3, 43.7.0, 44.3.0, and 45.0.0-alpha.5.

Affected: npm: electron

### Impact Requests to open external protocol URLs could be attributed to a document other than the one that asked for them, so the `requestingUrl` passed to `session.setPermissionRequestHandler` was a trusted origin for a launch untrusted content had requested. An origin-based handler could therefore let untrusted content launch an OS-registered external application.

Apps are only affected if they grant `openExternal` based on the requesting origin and let untrusted content open or navigate windows. Apps whose permission handler denies `openExternal` for untrusted content are not affected.

### Workarounds Deny the `openExternal` permission for untrusted content, or deny the windows it opens with `setWindowOpenHandler`.

### Fixed Versions * `45.0.0-alpha.5` * `44.3.0` * `43.7.0` * `42.11.3`

### For more information If you have any questions or comments about this advisory, email us at [security@electronjs.org](mailto:security@electronjs.org)