Impact
Apps that expose Promise-returning functions to web content via contextBridge may be vulnerable to a context isolation bypass. Untrusted web content could obtain access to the isolated preload world and, through it, every capability the preload script has. In renderers without a sandbox, or with nodeIntegration enabled, this may escalate to Node.js access.
Apps are affected if they expose Promise-returning functions via contextBridge — the standard pattern for wrapping ipcRenderer.invoke — in windows that load untrusted content. Apps that never load untrusted content in those windows are not affected.
Workarounds
There are no app side workarounds, you must update to a patched version of Electron.
Fixed Versions
42.0.0-beta.5
41.2.2
40.9.2
39.8.9
For more information
If you have any questions or comments about this advisory, email Electron at security@electronjs.org