Context isolation bypass via nested unserializable return value in Electron

Electron is a framework which lets you write cross-platform desktop applications using JavaScript, HTML and CSS. Electron apps using contextIsolation and contextBridge are affected. This is a context isolation bypass, meaning that code running in the main world context in the renderer can reach into the isolated Electron context and perform privileged actions. This issue is only exploitable if an API exposed to the main world via contextBridge can return an object or array that contains a javascript object which cannot be serialized, for instance, a canvas rendering context. This would normally result in an exception being thrown Error: object could not be cloned. The app side workaround is to ensure that such a case is not possible. Ensure all values returned from a function exposed over the context bridge are supported. This issue has been fixed in versions 25.0.0-alpha.2, 24.0.1, 23.2.3, and 22.3.6.